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1.
PEEK versus metal cages in posterior lumbar interbody fusion: a clinical and radiological comparative study.
Cuzzocrea, F, Ivone, A, Jannelli, E, Fioruzzi, A, Ferranti, E, Vanelli, R, Benazzo, F
Musculoskeletal surgery. 2019;(3):237-241
Abstract
BACKGROUND Low back pain and sciatica represent a common disabling condition with a significant impact on the social, working and economic lives of patients. Transforaminal lumbar interbody fusion (TLIF) is a surgical procedure used in degenerative spine conditions. Several types of cages were used in the TLIF procedure. PURPOSE To determine whether there is a difference in terms of symptomatology improvement, return to daily activities and fusion rate between metal cages and polyetheretherketone (PEEK) cages. METHODS We have retrospectively reviewed 40 patients who have undergone TLIF from October 2015 to May 2016. All patients were clinically evaluated with questionnaires and were assessed with CT scan and standing X-ray films of the full-length spine. RESULTS We found no significant functional differences in the two groups. At 1-year follow-up, osteolysis was present in 50% of cases of the PEEK cages and in 10% cases of the metal cages. The degree of fusion at 1 year was evaluated as complete in 40% cases of the metal cages and 15% cases of the PEEK cages. CONCLUSIONS We have found a better fusion rate and prevalence of fusion in the group treated with metal cages, reflecting the well-known osteoinductive properties of titanium and tantalum.
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Additive manufacturing of biodegradable metals: Current research status and future perspectives.
Qin, Y, Wen, P, Guo, H, Xia, D, Zheng, Y, Jauer, L, Poprawe, R, Voshage, M, Schleifenbaum, JH
Acta biomaterialia. 2019;:3-22
Abstract
The combination of biodegradable metals and additive manufacturing (AM) leads to a revolutionary change of metal implants in many aspects including materials, design, manufacturing, and clinical applications. The AM of nondegradable metals such as titanium and CoCr alloys has proven to be a tremendous success in clinical applications. The AM of biodegradable metals including magnesium (Mg), iron (Fe), and zinc (Zn) is still in its infancy, although much progress has been made in the research field. Element loss and porosity are common processing problems for AM of biodegradable metals like Zn and Mg, which are mainly caused by evaporation during melting under a high-energy beam. The resulting formation quality and properties are closely related to material, design, and processing, making AM of biodegradable metals a typical interdisciplinary subject involving biomaterials, mechanical engineering, and medicine. This work reviews the state of research and future perspective on AM of biodegradable metals from extensive viewpoints such as material, processing, formation quality, design, microstructure, and properties. Effects of powder properties and processing parameters on formation quality are characterized in detail. The microstructure and metallurgical defects encountered in the AM parts are described. Mechanical and biodegradable properties of AM samples are introduced. Design principles and potential applications of biodegradable metal implants produced by AM are discussed. Finally, current research status is summarized together with some proposed future perspectives for advancing knowledge about AM of biodegradable metals. STATEMENT OF SIGNIFICANCE Rapid development of research and applications on biodegradable metals and additive manufacturing (AM) has been made in recent years. Customized geometric shapes of medical metals with porous structure can be realized accurately and efficiently by laser powder bed fusion (L-PBF), which is beneficial to achieve reliable stress conduction and balanced properties. This review introduces the development history and current status of AM of biodegradable metals and then critically surveys L-PBF of Mg-, Fe-, and Zn-based metals from multiple viewpoints including materials, processing, formation quality, structural design, microstructure, and mechanical and biological properties. The present findings are summarized together with some proposed future challenges for advancing AM of biodegradable metals into real clinical applications.
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Revisiting the insights and applications of protein engineered hydrogels.
J, B, Chanda, K, M M, B
Materials science & engineering. C, Materials for biological applications. 2019;:312-327
Abstract
Utilization of protein-protein interactions or protein-peptide interactions has led to new crosslinking chemistries, resulting into protein hydrogels. Enzyme catalyzed crosslinking of specific amino acids has also been used to generate crosslinked protein hydrogels. Weak, temporary, reversible or non-covalently crosslinked protein gels as well as strong, permanent, irreversible or covalently crosslinked protein gels with mechanical strengths of varying degrees are generated by means of various crosslinking strategies. These protein hydrogels are tailored by means of protein engineering and recombinant DNA technology, depending on its end use as scaffolds for specific tissue engineering, drug delivery, wound dressings etc. This review aims to cover the advancements in the use of protein engineering along with different crosslinking techniques to create novel protein hydrogels that finds various applications in biomedical industries.
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Ureteral Obstruction After Endoscopic Treatment of Vesicoureteral Reflux: Does the Type of Injected Bulking Agent Matter?
Friedmacher, F, Puri, P
Current urology reports. 2019;(9):49
Abstract
PURPOSE OF REVIEW Endoscopic injection of bulking agents for the treatment of vesicoureteral reflux (VUR) has become a therapeutic alternative to antibiotic prophylaxis and ureteral reimplantation. Although considered as a safe and efficient procedure, several studies have reported cases of ureteral obstruction (UO) after endoscopic correction of VUR. This review article evaluates the present VUR literature to estimate the incidence of UO following endoscopic injection of different substances, while also discussing the impact of injection technique and implant volume. RECENT FINDINGS Twenty-five publications were identified that provided detailed information on 64 females and 32 males (age range, 7 months-48 years) that developed UO after endoscopic treatment of VUR using dextranomer/hyaluronic acid (Dx/HA), polyacrylate polyalcohol (PP), polydimethylsiloxane (PDMS), calcium hydroxyapatite (CaHA), polytetrafluoroethylene (PTFE), or collagen. There was some variation in the reported incidence of UO among these materials: Dx/HA (0.5-6.1%), PP (1.1-1.6%), PDMS (2.5-10.0%), CaHA (1.0%), and PTFE (0.3%). Postoperative UO was described following subureteric transurethral injection (STING), intraureteric hydrodistension implantation technique (HIT), combined HIT/STING and double HIT. The injected volume ranged widely, also depending on the type of bulking agent: Dx/HA (0.3-3.0 mL), PP (0.3-1.2 mL), PDMS (1.0-2.2 mL), CaHA (0.4-0.6 mL), and PTFE (1.5-2.0 mL). The timing of UO varied from immediately after the procedure to 63 months. Over half of patients showed asymptomatic hydroureteronephrosis on follow-up imaging, whereas the remaining presented with symptoms of acute UO or fever. UO remains a rare complication after endoscopic correction of VUR, generally reported in less than 1% of treated cases, which appears to be independent of the injected substance, volume, and technique. However, long-term follow-up is recommended as asymptomatic or delayed UO can occur, potentially leading to deterioration of renal function.
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Recombinant Human Platelet-Derived Growth Factor BB in Combination With a Beta-Tricalcium Phosphate (rhPDGF-BB/β-TCP)-Collagen Matrix as an Alternative to Autograft.
Daniels, TR, Anderson, J, Swords, MP, Maislin, G, Donahue, R, Pinsker, E, Quiton, JD
Foot & ankle international. 2019;(9):1068-1078
Abstract
BACKGROUND Joint arthrodesis often employs autograft to promote union; graft harvesting can lead to perioperative morbidity. A Canadian randomized controlled trial (RCT) demonstrated that recombinant human platelet-derived growth factor BB homodimer (rhPDGF-BB) combined with beta-tricalcium phosphate (β-TCP)-collagen was a safe, effective alternative to autograft. This multicenter North American RCT compared the safety and efficacy of rhPDGF-BB/β-TCP-collagen with autograft for ankle and hindfoot fusion. Subclassification using propensity scores (PS) incorporated patients from previous trials for enhanced statistical power for noninferiority testing and broader review of treatments. METHODS Patients requiring ankle or hindfoot arthrodesis and supplemental bone graft were treated with rhPDGF-BB/β-TCP-collagen (n = 69) or autograft (n = 35). Outcomes included joint fusion on computed tomography (24 weeks), clinical healing status, visual analog scale (VAS) pain, Short-Form 12 (SF-12), American Orthopaedic Foot & Ankle Society (AOFAS) Ankle-Hindfoot Scale, and Foot Function Index (FFI) scores over 52 weeks. PS methodology addressed potential selection bias arising from pooling data among these patients and 2 previous RCTs with similar inclusion criteria, surgical techniques, graft harvest techniques, and outcomes. All 132 rhPDGF-BB/β-TCP-collagen-treated patients and 167 of 189 candidate autograft-treated controls were selected for comparison by an independent statistician blinded to outcomes. RESULTS In the PS subclassification, 68.1% treatment patients and 68.4% controls achieved >50% osseous bridging at fusion sites. Clinical healing status was achieved in 84.8% of treated patients and 90.7% of controls at 52 weeks. Clinical, functional, and quality of life results demonstrated noninferiority of rhPDGF-BB/β-TCP-collagen to autograft. Safety-related outcomes were equivalent. CONCLUSION PS subclassification analysis of 3 RCTs demonstrated that rhPDGF-BB/β-TCP-collagen was as effective as autograft for ankle and hindfoot fusions, with less pain and morbidity than treatment with autograft. LEVEL OF EVIDENCE Level I, prospective randomized study.
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Does the association of blood-derived growth factors to nanostructured carbonated hydroxyapatite contributes to the maxillary sinus floor elevation? A randomized clinical trial.
de Almeida Barros Mourão, CF, Lourenço, ES, Nascimento, JRB, Machado, RCM, Rossi, AM, Leite, PEC, Granjeiro, JM, Alves, GG, Calasans-Maia, MD
Clinical oral investigations. 2019;(1):369-379
Abstract
OBJECTIVE The combination of calcium phosphate with blood-derived growth factors (BDGF) has been widely used in bone regeneration procedures although its benefits are still unclear. The purpose of this study was to evaluate whether or not BDGF improves the efficacy of a modified carbonated calcium phosphate biomaterial in sinus floor augmentation. MATERIAL AND METHODS Ten patients underwent 20 sinus floor augmentation procedures using nanostructured carbonated hydroxyapatite (cHA) microspheres alone or associated with BDGF in a randomized controlled clinical trial. The in vitro release of growth factors was assessed by an elution assay. Bone grafts were randomly implanted in the right and left maxillary sinuses of each participant, associated either with a 0.9% saline solution or BDGF. Bone gain was evaluated through cone beam tomography after 180 days. RESULTS Nine women and one man composed the sample. The blood-derived concentrates were able to release high levels of growth factors and cytokines. A significant clinical advantage was observed in the use of the BDGF after fibrin polymerization around the biomaterial microspheres, optimizing the surgical procedures, thereby reducing the time and displacement, and improving the adaptation of the biomaterial in the maxillary sinus. No synergistic effect was observed in bone formation when cHA was associated with BDGF (p > 0.05). CONCLUSION Equivalent new bone formation was observed for cHA in the presence or absence of the BDGF concentrate in bilateral sinus floor elevation after 6 months. Blood-derived growth factors did not improve bone repair when associated with calcium phosphate in sinus lift procedures.
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Feasibility and safety of treating non-unions in tibia, femur and humerus with autologous, expanded, bone marrow-derived mesenchymal stromal cells associated with biphasic calcium phosphate biomaterials in a multicentric, non-comparative trial.
Gómez-Barrena, E, Rosset, P, Gebhard, F, Hernigou, P, Baldini, N, Rouard, H, Sensebé, L, Gonzalo-Daganzo, RM, Giordano, R, Padilla-Eguiluz, N, et al
Biomaterials. 2019;:100-108
Abstract
BACKGROUND ORTHO-1 is a European, multicentric, first in human clinical trial to prove safety and feasibility after surgical implantation of commercially available biphasic calcium phosphate bioceramic granules associated during surgery with autologous mesenchymal stromal cells expanded from bone marrow (BM-hMSC) under good manufacturing practices, in patients with long bone pseudarthrosis. METHODS Twenty-eight patients with femur, tibia or humerus diaphyseal or metaphyso-diaphyseal non-unions were recruited and surgically treated in France, Germany, Italy and Spain with 100 or 200 million BM-hMSC/mL associated with 5-10 cc of bioceramic granules. Patients were followed up during one year. The investigational advanced therapy medicinal product (ATMP) was expanded under the same protocol in all four countries, and approved by each National Competent Authority. FINDINGS With safety as primary end-point, no severe adverse event was reported as related to the BM-hMSC. With feasibility as secondary end-point, the participating production centres manufactured the BM-hMSC as planned. The ATMP combined to the bioceramic was surgically delivered to the non-unions, and 26/28 treated patients were found radiologically healed at one year (3 out of 4 cortices with bone bridging). INTERPRETATION Safety and feasibility were clinically proven for surgical implantation of expanded autologous BM-hMSC with bioceramic. FUNDING EU-FP7-HEALTH-2009, REBORNE Project (GA: 241876).
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Development, Characterization and In Vitro Biological Properties of Scaffolds Fabricated From Calcium Phosphate Nanoparticles.
Morejón, L, Delgado, JA, Antunes Ribeiro, A, Varella de Oliveira, M, Mendizábal, E, García, I, Alfonso, A, Poh, P, van Griensven, M, Balmayor, ER
International journal of molecular sciences. 2019;(7)
Abstract
Ceramic materials mimic the mineral composition of native bone and feature osteoconductive properties; they are therefore used to regenerate bone tissue. Much research focuses on increasing the porosity and pore interconnectivity of ceramic scaffolds to increase osteoconductivity, cell migration and cell-cell interaction. We aimed to fabricate biocompatible 3D-scaffolds featuring macro- and microporous calcium phosphates with high pore interconnection. Nanoparticles of hydroxyapatite (HA) and calcium deficient hydroxyapatite (CDHA) were synthesized by wet chemical precipitation. Scaffolds were produced from them by the replication polymeric foam technique. Solid content and sintering temperature were varied. Nanoparticles and scaffolds were characterized regarding morphology, chemical and mineral composition, porosity and mechanical properties. Biocompatibility, cell attachment and distribution were evaluated in vitro with human adipose mesenchymal stem cells. Scaffolds with total porosity of 71%-87%, pores in the range of 280-550 µm and connectivity density up to 43 mm-3 were obtained. Smaller pore sizes were obtained at higher sintering temperature. High solid content resulted in a decrease of total porosity but increased interconnectivity. Scaffolds 50HA/50β-TCP featured superior interconnectivity and mechanical properties. They were bioactive and biocompatible. High HA solid content (40 wt.%) in the HA pure scaffolds was negative for cell viability and proliferation, while in the 50HA/50β-TCP composite scaffolds it resulted more biocompatible.
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9.
Protein-Engineered Functional Materials.
Wang, Y, Katyal, P, Montclare, JK
Advanced healthcare materials. 2019;(11):e1801374
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Abstract
Proteins are versatile macromolecules that can perform a variety of functions. In the past three decades, they have been commonly used as building blocks to generate a range of biomaterials. Owing to their flexibility, proteins can either be used alone or in combination with other functional molecules. Advances in synthetic and chemical biology have enabled new protein fusions as well as the integration of new functional groups leading to biomaterials with emergent properties. This review discusses protein-engineered materials from the perspectives of domain-based designs as well as physical and chemical approaches for crosslinked materials, with special emphasis on the creation of hydrogels. Engineered proteins that organize or template metal ions, bear noncanonical amino acids (NCAAs), and their potential applications, are also reviewed.
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10.
Demineralized Bone Matrix Carriers and their Clinical Applications: An Overview.
Zhang, H, Yang, L, Yang, XG, Wang, F, Feng, JT, Hua, KC, Li, Q, Hu, YC
Orthopaedic surgery. 2019;(5):725-737
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Abstract
Reconstruction of massive bone defects is challenging for orthopaedic clinicians, especially in cases of severe trauma and resection of tumors in various locales. Autologous iliac crest bone graft (ICBG) is the "gold standard" for bone grafting. However, the limited availability and complications at donor sites resulted in seeking other options like allografts and bone graft substitutes. Demineralized bone matrix (DBM) is a form of allograft using acidic solution to remove mineral components, while leaving much of the proteinaceous components native to bone, with small amounts of calcium-based solids, inorganic phosphates, and some trace cell debris. It is an osteoconductive and osteoinductive biomaterial and is approved as a medical device for use in bone defects and spinal fusion. To pack consistently into the defect sites and stay firmly in the filling parts, DBM products have various forms combined with biocompatible viscous carriers, including sponges, strips, injectable putty, paste, and paste infused with chips. The present review aims to summarize the properties of various kind of viscous carriers and their clinical use combined with DBM in commercially available products. Given DBM'mercially available products. Given DBM;s long clinical track record and commercial accessibility in standard forms, opportunities to further develop and validate DBM as a versatile bone biomaterial in orthopaedic repair and regenerative medicine contexts are attractive.