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Results for “Absorbable Implants”

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At least 109 records · Page 6Linked to original sources
PubMed1997

[A biomechanical study on the bone repairing ability of recombinant human bone morphogenetic protein-2-coral composited artificial bone].

To improve bone repairing ability of coral, recombinant human bone morphogenetic protein-2 (rhBMP-2)-coral composited artificial bone was obtained by combining coral with rhBMP-2 in this experiment. The composite was implanted into rabbit calvarial critical-size defects and coral alone was implanted as control. The bone repairing ability was assessed by radiography, histology and biomechanics. The results showed that implants were absorbed gradually after they was implanted into the defects. In the meantime, the new bone was formed and the mechanical strength was reinforced uninterruptedly in bone defect regions. At 12 weeks, the implants were replaced completely by bone, and the mechanical strength was entirely restored. These suggest that the composite possess a superior bone repairing ability and may be one of the most perfect bone graft substitutes currently available.

Animals↗
PubMed1995

[Absorbable SR-PGA implant in orthopaedics: preliminary results of treatment of fractures].

This article reports preliminary results of treatment in 33 patients with 36 cancellous bone fractures using absorbable rods and screws of self-reinforced polyglycolide (SR-PGA). Plaster cast was used postoperatively for 3 weeks. All fractures but one lateral ankle fracture were fixed until healed without displacement. All of them healed at six weeks after trauma. No wound infection and fluid accumulation occurred. This new device is an ideal implant for fixation of cancellous bone fracture.

Adolescent↗
PubMed1988

Influence of nonbiologic implants on laminectomy membrane formation in dogs.

The effects of various surgical implants, spinal cord hypothermia, and glucocorticoid administration on formation of the laminectomy membrane were evaluated in 32 preconditioned chondrodystrophoid dogs. Modified dorsal laminectomies and full-length durotomies, from T12 to L1, were performed on all dogs. Dogs were allotted to 2 groups. Group-1 dogs (n = 20) were further allocated to 4 subgroups (a, b, c, and d) consisting of 5 dogs each. Group-1a dogs received no implant, group-1b dogs had absorbable gelatin sponges implanted, group-1c dogs had absorbable gelatin films implanted, and group-1d dogs had absorbable gelatin sponges and absorbable gelatin films implanted. Daily neurologic examinations permitted correlation of neurologic dysfunction with secondary spinal cord compression in those dogs in which it developed. The influence of these implants on laminectomy membrane formation and dural healing was assessed by gross and microscopic evaluation of transverse sections of the vertebrae and spinal cord after euthanasia of one member of each subgroup at 1, 2, 4, 8, and 16 weeks after surgery. Group-2 dogs (n = 12) were further allotted to 3 subgroups (a, b, and c) consisting of 4 dogs each. One dog in each group-2 subgroup underwent the same surgical procedures described for the group-1 subgroups (ie, 4 procedures/group-2 subgroup). The additional effects of 3 conventional supportive techniques (selective regional spinal cord hypothermia, glucocorticoid administration, or spinal cord hypothermia and glucocorticoid administration) on laminectomy membrane formation and on immediate postoperative recovery were examined in groups 2a, 2b, and 2c, respectively. Neurologic examinations were performed daily until this time. All dogs in group 2 were euthanatized 1 week after surgery for gross and microscopic examination of transverse sections of the vertebrae and spinal cord. Qualitative histopathologic effects of the different implants and supportive techniques on formation of the laminectomy membrane were determined. Statistical analysis of the degrees of secondary spinal cord compression was performed in group-1 dogs by measuring and comparing ratios of the vertical to the horizontal diameters of the transverse spinal cord sections from locations within (T12 to L1) and out of (T11, T11-12, L1-2, and L2) the region of surgical intervention. The vertical/horizontal diameter ratios measured from transverse sections from T11 to L2 in size-matched, untreated control dogs formed the standards for a mean roundness index of the spinal cord in the various anatomic locations of the vertebral column.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1999

Periodontal repair in dogs: effect of rhBMP-2 concentration on regeneration of alveolar bone and periodontal attachment.

The objective of this study was to evaluate the effect of recombinant human bone morphogenetic protein-2 (rhBMP-2) concentration on regeneration of alveolar bone and cementum, and on associated root resorption and ankylosis. Contralateral, critical size, supra-alveolar, periodontal defects were surgically produced and immediately implanted with rhBMP-2 in an absorbable collagen sponge (ACS) carrier in 8, young adult, male, beagle dogs. 6 animals received rhBMP-2/ACS (rhBMP-2 at 0.05, 0.10, or 0.20 mg/mL; total construct volume/defect approximately 4.0 mL) in contralateral defects following an incomplete block design. 2 animals received rhBMP-2/ACS (rhBMP-2 at 0 and 0.10 mg/mL) in contralateral defects (controls). The animals were euthanised at 8 weeks post-surgery and block sections of the defects were collected for histologic and histometric analysis. Supra-alveolar periodontal defects receiving rhBMP-2 at 0.05, 0.10, or 0.20 mg/ml exhibited extensive alveolar regeneration comprising 86%, 96%, and 88% of the defect height, respectively. Cementum regeneration encompassed 8%, 6%, and 8% of the defect height, respectively. Root resorption was observed for all rhBMP-2 concentrations. Ankylosis was observed in almost all teeth receiving rhBMP-2. Control defects without rhBMP-2 exhibited limited, if any, evidence of alveolar bone and cementum regeneration, root resorption, or ankylosis. Within the selected rhBMP-2 concentration and observation interval, there appear to be no meaningful differences in regeneration of alveolar bone and cementum. There also appear to be no significant differences in the incidence and extent of root resorption and ankylosis, though there may be a positive correlation with rhBMP-2 concentration.

Absorbable Implants↗
PubMed2001

[Carboxymethylcellulose hydrogel-filled breast implants. Our experience in 15 years].

The author reports 15 years of laboratory and surgical experience with the use of breast implants pre-filled with carboxy-methyl-cellulose gel which he has used since 1984. Laboratory tests and results are presented. The author has undertaken a retrospective analysis of 380 clinical cases since 1984. He concludes that there is a future role for breast implants containing a non-toxic, visco-elastic and biodegradable filling gel in conjunction with the manufacture of increasingly reliable implant linings.

Absorbable Implants↗
PubMed2000

Do your membranes have enough space?

Space is a critical requirement of guided bone regeneration using membrane techniques. This paper discusses the role space may play in the use of GBR in conjunction with osseo-integrated implants.

Absorbable Implants↗
PubMed2002

The effect of therapeutic irradiation on LactoSorb absorbable copolymer.

Bioabsorbable implants continue to gain popularity in providing temporary internal fixation due to their many advantages over metallic internal fixation. Coincident with the presence of internal fixation devices, it may be necessary to use radiotherapy to treat tumors. While metal implants can alter the distribution of the radiotherapy beam, bioabsorbable polymer implants are, essentially, tissue equivalent. This ionizing irradiation, in sufficiently high dose, can affect polymers through chain scission and cross-linking and accelerate the hydrolysis of absorbable polymers. However, little is known about the effects of therapeutic doses on such materials. This study exposed LactoSorb (Biomet, Inc., Warsaw, IN) absorbable copolymer to doses of x-ray irradiation in a clinically relevant manner, in vitro, with individual doses of 2 Gy administered five days per week for up to eight weeks, yielding a total cumulative dose of up to 80 Gy. Specimens were tested both mechanically and for inherent viscosity. Overall, the LactoSorb specimens withstood exposure to the irradiation exceedingly well, providing empirical evidence of the suitability of this material for temporary internal fixation when subsequent radiotherapy in the region is probable.

Absorbable Implants↗
PubMed1990

A histomorphological study on self-reinforced polyglycolide (SR-PGA) osteosynthesis implants coated with slowly absorbable polymers.

A total of 150 osteotomies of rabbits' distal femur were fixed with absorbable self-reinforced polyglycolide (SR-PGA) rods coated with slowly absorbable polymers. In order to reduce the degradation rate of the SR-PGA construction rods were coated with n-butyl-2-cyanoacrylate, polydioxanone (PDS), poly-beta-hydroxybutyrate (PHBA), or poly-l-lactide (PLLA). Biocompatibility and the rate of biodegradation were evaluated in histological, histomorphometric, microradiographic, and oxytetracycline labeling studies. PDS, PHBA, and PLLA coatings showed good biocompatibility although there were scattered fluid accumulations around the rod in each group. Cyanoacrylate coating seemed to inhibit cartilage regeneration and cause the formation of considerable amount of connective tissue around the implant. The PGA core of the rod had totally degraded in 24 to 36 weeks in each coating group. Cyanoacrylate and PDS coatings were not detectable after 6 weeks while PHBA and PLLA coatings were still observed after 48 weeks. There were five (14%) non-unions in the cyanoacrylate coating group, one (3%) in the PHBA coating group caused by a purulent infection and none in the PDS and PLLA coating groups.

Absorption↗
PubMed2000

Clinical and histological results of septoplasty with a resorbable implant.

BACKGROUND: The use of a resorbable implant connected with septal cartilage would facilitate external septoplasty, offering mechanical stability until the cartilage fragments heal. OBJECTIVE: To study the histological and clinical results of septoplasty with a resorbable implant (polydioxanone [PDS; Ethicon, Norderstedt, Germany]) in conjunction with cartilage. DESIGN: To provide histological information in 5 rabbits, PDS foil was implanted into the outer ear in conjunction with an artificial cartilage defect. Observations were made at 2, 5, 10, 15, and 25 weeks. Resorption of the implant was investigated, including the time to complete elimination. In addition, septoplasty with PDS foil was performed on 71 patients with severe septal deformities. Surgery consisted of excision of the quadrilateral cartilage and division into straight fragments, which were sutured to the PDS foil and replaced as a free graft. SETTING: Ear, nose, and throat department of the General District Hospital Steyr, Steyr, Austria. RESULTS: Histological examination showed that the foil remained unchanged for at least 10 weeks and was completely resorbed after 25 weeks with minimal remaining scar tissue. Newly formed cartilage developed bordering the cartilage defect. In the clinical study, all patients experienced varying degrees of improvement in nasal blockage. No immediate or long-term complications occurred. CONCLUSIONS: The use of PDS foil in connection with cartilage facilitates surgical correction of severe septal deformities, additionally providing support for the nasal dorsum. The histological examination showed that no inflammatory or foreign body reaction occurred. Cartilage regeneration was even found. The foil was completely resorbed within 25 weeks, avoiding the long-term complications that occur with other artificial implants.

Absorbable Implants↗
PubMed2003

Instrument for extraction socket measurement in immediate implant installation.

The aim of the present study was to create an instrument and a computer program for measurement of extraction sockets and for planning of the immediate replacement of teeth using screw-shaped dental implants. Ten titanium screw-shaped Osteofix Dental Implant System implants (Osteofix, Oulu, Finland) were immediately installed after extraction in nine patients, four women and five men (age 17-62 years). The measurements of fresh extraction sockets were taken at six points (mesio-buccal, buccal, disto-buccal, disto-lingual, lingual and mesio-lingual) using an instrument created by the author. The area of no contact between bone and dental implant was 11-40% (mean 31%, SD 9%), calculated by computer program. If less than 30% of the implant surface area would be in contact with the bone, immediate replacement was abandoned because sufficient primary stability could not be achieved. Guided bone regeneration was promoted by covering the implant and bone defect with deproteinized bovine bone mineral (Bio-Oss, Geistlich AG, Wolhusen, Switzerland) and bioresorbable collagen membrane (Bio-Gide, Geistlich AG), fixed in place with resorbable pins (Resor Pin, Geistlich AG). After 6 months a considerable, statistically significant (P < 0.05) defect reduction of 90% (SD 7%) was noted. It was concluded that an instrument and a computer program created for extraction socket measurement are useful in some borderline cases when there is lack of bone and the success of one-stage implantation is doubtful.

Absorbable Implants↗
PubMed2002

Maxillary sinus augmentation using prehardened calcium sulfate: a case report.

Prehardened medical-grade calcium sulfate hemihydrate was placed as a grafting material for sinus floor elevation in the left posterior maxilla. After 8 months of healing, three titanium plasma-sprayed screw implants (Biolock) were placed. At the same time, a bone biopsy was harvested for histologic evaluation. The specimen was processed according to standard techniques for hard tissue histology. In both the grafted area and the previously existing area of sinus floor, the histology showed complete calcium sulfate resorption and the bone was primarily of lamellar structure. In the 5-month radiograph, a new trabecular design appeared from the periphery of the grafted area, and on the 8-month radiograph, the graft material was no longer detectable and the augmented area was filled by new tissue showing a trabecular design. This case report documented that medical-grade calcium sulfate hemihydrate, when used as a grafting material for augmentation of the sinus floor, may lead to proper osseointegration of dental implants.

Absorbable Implants↗
PubMed2001

Chondral injury from bioabsorbable screws after meniscal repair.

A case of chondral injury after medial meniscal repair with a headless bioabsorbable screw is reported. As these implants can take a long time to be absorbed, all arthroscopic surgeons should be aware of possibility of this complication during this period.

Absorbable Implants↗
PubMed1987

[Semirigid plate osteosyntheses using absorbable polymers as temporary implants. II. Animal experiment studies].

Polylactide-l test rods showed an initial stability of 130 N/mm2 in the three-point bending test; the stability decreased after implantation in the dorsal muscle of the rat within 5 weeks to about half the initial value. The copolymer materials showed less initial strength, and the stability decreased under the same conditions much earlier. All materials showed good tissue compatibility. After a transverse section of the beagle radius was stabilized with plates and screws out of polylactide-l, a delayed bony union with callus formation was observed.

Absorption↗
PubMed1987

[Semirigid plate osteosyntheses using absorbable polymers as temporary implants. I. Introduction, chemical composition and material-related studies].

Possible indications for the use of biodegradable implants are presented and the chemical compounds in question are briefly described. The results of a laboratory investigation to determine mechanical stability, tensile strength and molecular weight are reported, in order to characterize the polymers and co-polymers of the lactide under study.

Absorption↗
PubMed2000

Bioresorbable polymers in trauma and bone surgery.

During the last few decades interest in resorbable polymeric materials has been steadily increasing. As with other materials for implantable devices, they have to satisfy several biological and technical requirements. Implants should maintain adequate mechanical properties in vivo for the time required and degrade at an effective rate. The conditions of polymer synthesis, further processing into implants and the sterilization process determine the mechanical properties of resorbable implants. Degradation of implants is manifested by implant fragmentation, strength loss and the decrease of polymer molecular weight. The rate of degradation and the tissue reaction are strongly affected by the material chemical composition and to some extent also by the mechanical properties. Potentially, devices made from bioresorbable polymers can overcome problems associated with metal implants like stress protection, potential for corrosion, wear and debris formation, as well as the necessity of implant removal. Resorbable polymers have proven to be good materials for a range of devices in trauma surgery. However, modifications and optimizations are still required. Three-dimensional porous scaffolds in various geometrical forms offer a good potential for the manufacture of tissue-engineered implants in the future.

Absorbable Implants↗