[Substitution of tumorous bone segments by Palacos].
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Adolescent↗
SEARCH · PubMed Health
Results for “Bone Substitutes”
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
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Structural changes of cortical bone in secondary hyperparathyroidism: replacement of lamellar bone by woven bone.
In femoral cortical bone of 16 uremic patients with long standing renal insufficiency an increased fraction of woven bone was found both in Haversian and in interstitial bone. Either partly resorbed Haversian systems were replaced by non lamellar woven bone or single Haversian systems showed partly well organized lamellar bone and partly disorganized non lamellar texture without signs of antecedent resorption. The replacement of lamellar bone by woven bone was measured morphometrically in undecalcified ground sections. Woven bone was defined by its lack of structural birefringence under polarized light. In advanced cases of secondary hyperparathyroidism more than 60% of cortical bone were composed of woven bone. The substitution of immature less organized woven bone for mature well orfanized lamellar bone has important implications for the biomechanical properties of the skeleton.
Adult↗
Shear strength of self-curing acrylic cement.
The average shearing strength of surgical Simplex P bone cement has been experimentally evaluated and found to be 5,762 plus or minus 180 psi. The average shearing strength for compact bone is about 10,000 psi. Therefore surgical Simplex P does not resist shear forces as well as compact bone and should not be used as a substitute for bone whenever possible. The inclusion of 10 per cent barium sulfate U.S.P. for radiographic purposes does not adversely affect the shear strength of the cement. This amount of barium is the same percentage by weight as that found in radiopaque Simplex P in clinical usage today. Varying the loading rate between 0.005 and 0.5 in/min slightly affected the magnitude of the shear force at failure. A comparison of the effect of short term curing times on the magnitude of the shear force at failure reveals that surgical Simplex P strengthens with time. The curing periods varied from 2 to 168 hours.
Acrylic Resins↗
[Substitution of the frontal bone with silicon].
The good results obtained with silicon implants used in the frontal region are reported by the authors. After the correct primary treatment the reconstructive operations have been performed at the least 6 months after the lesion, if the environment of the defect was free from any reaction during this time. 14 implantations have been performed in 2 years. Satisfactory functional and cosmetic results were obtained and the implant was to be removed in no case.
Elasticity↗
[Free bone transplant as mandibular substitute with special reference to chin reconstruction].
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Chin↗
[Autologous substitution of short hollow bones].
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Adult↗
[The histological reaction of cialit preserved hyaline and elastic cartilage implanted to replace partially bony wall of the guinea-pig bulla (author's transl)].
Cialit preserved cartilage was used to fill defects of the bulla of porpoises and the histological healing was studied. Hyaline and elastic cartilage are showing an integration without reactions. The cartilage is resorbed consecutively by the recipient and substituted by bone. Whereas the hyaline cartilage shows a complete bony substitute and a small enlargement we can registrate that the elastic cartilage often shows a resorptive tendency with replacement of connective tissue and loss of the shape. The histological results are corresponding to the clinical results when using preserved cartilage in middle ear surgery for restoring the posterior wall.
Age Factors↗
Autologous bone grafts versus alloplastic implants for orbital floor reconstruction: a systematic review and meta-analysis.
PURPOSE: The choice of reconstructive material for orbital floor fractures remains a subject of debate. While autologous bone has historically been considered the "gold standard," alloplastic implants offer potential advantages in reducing surgical morbidity. This meta-analysis aimed to compare the safety and efficacy of autologous bone grafts versus alloplastic implants in orbital floor reconstruction. METHODS: A systematic review was conducted in accordance with PRISMA guidelines (PROSPERO: CRD420251140583). Electronic databases (PubMed, Scopus, Web of Science, Cochrane Library) were searched from inception to August 2025. Randomized controlled trials and comparative cohort studies evaluating functional outcomes (diplopia, enophthalmos) and complications (ectropion, infection, malposition) were included. Data were synthesized using a random-effects model, with risk ratios (RR) and 95% confidence intervals (CI) calculated. RESULTS: Twenty studies comprising 2,119 patients were included. Alloplastic implants demonstrated statistically significant superiority in periocular safety, with a reduced risk of postoperative ectropion compared to autologous grafts (RR = 2.245; p = 0.020). In an exploratory sensitivity analysis excluding one outlier study, autologous grafts were associated with a significantly higher risk of implant malposition (RR = 2.074; p = 0.004). Autologous reconstruction was associated with a strong trend toward increased postoperative pain (p = 0.052) and inherent donor-site morbidity. No statistically significant differences were observed regarding infection (p = 0.402), enophthalmos (p = 0.201), or diplopia (p = 0.221). CONCLUSION: Alloplastic implants were associated with a lower risk of ectropion and implant malposition, with functional outcomes statistically comparable to autologous bone. Given the elimination of donor-site morbidity, alloplastic biomaterials represent a safe and effective alternative for orbital floor reconstruction; however, the predominance of retrospective, heterogeneous studies in the current evidence base means these findings should inform, rather than replace, individualized surgical decision-making pending further high-quality randomized trials.
Humans↗
Ultrastructure of chondrogenetic interactions between bone matrix gelatin and mesenchymal cells.
The ultrastructure of post fetal chondrogenesis was investigated in chondrogenetic implants and explants of bone matrix gelatin: (A) in direct contact with living cells; (B) separated from living cells by cellulose acetate membranes; (C) in serum or in a culture medium with no contact with living cells. Ruthenium red (RR) staining coarse granules free of interconnecting filaments aggregated in interstitial fluid and inside the surface of the bone matrix gelatin within 72 hours in systems with either direct or indirect contact with living connective tissue cells. No RR granules formed when control denatured or autolysed bone matrix gelatin were substituted for undenatured bone matrix gelatin. No RR granules formed in bone matrix gelatin incubated in serums or media in the absence of living cells in the system. These observations suggest the possibility that 4 days before overt transmembrane cartilage cell differentiation, covert (presumptive) chondroblasts synthesize and secrete precursor substance for aggregation of filament-free RR granules. The relationship between chondromorphogenesis and filament-free RR granules requires further investigation.
Animals↗
Preleukemic change in the bone marrow of whole-body irradiated RFM/Up mice.
In the whole-body irradiated mouse, various late effects of radiation are observed after the recovery from acute radiation injury. Some of these account for the familiar proneness of certain mouse strains to develop leukemias. The two experiments described below were designed to (a) identify such preleukemic changes in blood-forming tissues and (b) to find ways to manipulate them experimentally with the purpose of preventing leukemia. Preleukemic change of the bone marrow appears to be a mere quantitative departure from normal in a qualitatively non-malignant tissue. It entails increased proneness of immature (precursor) cells to react with latent virus. Our data are consistent with the assumption that this proneness is enhanced (or brought about) by removal of a controlling influence exerted by the mature cells over their precursors (feed-back inhibition). Re-irradiation combined with intravenous bone marrow substitution offsets the leukemogenic influence of an earlier radiation exposure. The effect of re-irradiation on bone marrow displaying preleukemic lesions corroborates conclusions from earlier experiments on the nature of these lesions.
Animals↗
Articular cartilage transplantation.
This report describes the biopsy findings in four of 30 patients treated with cadaver osteochondral shell allografts for osteoarthritis in the knee. This study demonstrates that graft cartilage cells can survive in excess of 25 months, and that host bone can completely replace graft bone by creeping substitution. An inflammatory reaction in synovium and bone marrow was found in only one of four cases. Graft failure was related to prolonged down time of donor cartilage in one case and mechanical factors related to osteoarthritis in the apposing femoral surface in other cases. The clinical success of these grafts is attributed to the prolonged viability of cartilage cells, the capacity of host bone to join graft cartilage without histologic reaction, and the host's immunologic tolerance, which obviates the need for immunosuppressive therapy.
Aged↗
[Blood losses in injuries to and surgical interventions on the bones. Transfusion of blood and blood substitutes. Complications].
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Acid-Base Equilibrium↗
Sheehan's syndrome with complete bone marrow aplasia: long-term results of substitution therapy with hormones.
A case of Sheehan's syndrome with pancytopenia and bone marrow aplasia is presented. The diagnosis was made 6 years after an ante-partum haemorrhage. The presenting feature was an anaemia unresponsive to usual therapy. Hormonal therapy alone (cortisone and thyroid extract with triiodothyronin, oestrogen and progestogen given sequentially) produced full haematological recovery, which has continued for 2 years since the treatment was begun.
Adult↗
[Proceedings: Sheehan's syndrome with bone marrow aplasia. Results of the substitutive hormonal therapy (author's transl)].
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Anemia, Aplastic↗
[Granulocyte substitution in febrile leukemia patients with bone marrow aplasia. 1. Results of a prospective study].
A prospective, randomized study was performed in aplastic, granulocytopenic, infected patients with acute leukemia during induction therapy. 12 patients received antibiotics alone, and 13 received antibiotics plus 1.7-14.7 X 10(10) (MEAN 6.6 X 10(10) granulocytes by 1-5 (mean 2.7) daily transfusions. In 10 of 12 controls the infection resolved and remission was achieved with granulocyte counts greater than 500/mm3 15 +/- 9 days after randomization. In the transfused patients, infection was brought under control in 10 out of 13 and remission was achieved with granulocyte counts greater than 500/mm3 25+/- 11 days after randomization. Only one death due to infection was observed (6 days after randomization, control).
Anemia, Aplastic↗
[Allogeneic osteoplasty following tumour resection (author's transl)].
Replacement by allogeneic cold-preserved bone following resection of bone-tumours is a successful method. The substitution of the allogeneic bone is delayed. Extensive allogeneic osteoplasties should be performed in consideration of the donor-recipient-selection principle.
Adult↗
Metacarpal loss treated by metatarsal substitution.
In the hand severe trauma and tumours are the most frequent causes of loss of bone substance in the metacarpals. To save the function of the complete digital ray repair by bone grafting is essential. A technique is described for transferring all or part of a metatarsal bone as a hemiarticular graft for substituting metacarpal bone loss.
Bone Neoplasms↗
Ultrastructural observations of amorphous bone mineral in avian bone.
Mineral from medullary bone of three avian species was examined with the electron microscope in order to clarify the ultrastructure of amorphous bone mineral (ABM) in a mineralized tissue. Powders from freeze-dried bone revealed bone mineral with morphology and behavior identical to synthetic amorphous calcium phosphate (ACP). These powders exhibited spherically shaped particles 180--400 A in diameter with uniform electron density when viewed at low beam intensity. Thin sections of embedded freeze-dried bone also revealed spherically shaped particles 100--350 A in diameter with electron beam sensitivity characteristic of ACP. Regions of bone mineral with irregular outline and morphology were observed which closely resemble the discoidal form of synthetic ACP. More electron-dense spherical particles (150 A in diameter) could be seen budding from these regions. Some of these buds exhibited electronlucent centers characteristic of AMB. The inorganic nature of these features of bone mineral was confirmed using ultramicroincineration. Preliminary exploration of a freeze-substitution technique showed spherical bone mineral particles which were similar in morphology to those observed in freeze-dried samples. A limited degree of preservation of cellular material was observed using this freeze-substitution technique.
Animals↗