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Tiell SM, Chennoju M, Davis BL, Owusu-Danquah J. Effects of ultrasound settings on temperature changes in NiTi implants. Med Eng Phys 2024; 123:104081. [PMID: 38365335 DOI: 10.1016/j.medengphy.2023.104081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 11/30/2023] [Accepted: 12/03/2023] [Indexed: 02/18/2024]
Abstract
BACKGROUND Shape memory alloys (SMAs) are well-known for their unique ability to undergo a shape change in response to a thermal stimulus. A frequently-used SMA for biomedical devices is NiTi, although its superelastic features tend to be emphasized more than the ability to change shape. Minimally invasive NiTi implants which can reconfigure or adjust their shape across several temperature points could provide desirable surgical outcomes. For decades, therapeutic ultrasound has been used medically as a non-invasive method for tissue thermal therapy. Ultrasound's ability to quickly raise temperatures, and transcutaneously activate shape changes in NiTi implants is a novel approach for eliciting the martensitic thermoelastic transformation. METHODS The purpose of this study was to investigate the features of therapeutic ultrasound that correspond with temperature changes in different NiTi specimens. For this purpose, ultrasound was applied to two NiTi specimens for two minutes each at varying low- and high-frequency and power settings using a Sonicator 740 and a Dynatron 150. FINDINGS The baseline temperature for all 32 trials was room temperature (23.0 ± 1.7°C). This study successfully increased the specimen temperature with the application of Sonicator 740 and Dynatron 150 therapeutic ultrasound machines (2.2 ± 2.4°C and 1.5 ± 1.15°C, respectively). From the statistical analyses of the experimental data, it was clear that there is a significant difference between low- and high-power settings on mean temperature change using the Dynatron 150 (ANCOVA; p = 0.013). Interpretation Of clinical relevance, NiTi implants can quickly and easily increase in temperature when applying therapeutic ultrasound. Ultrasound power causes temperature changes and should be accounted for when designing orthopedic implants for applications where dimensional changes are desirable.
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Kwan JC, Flannagan RS, Vásquez Peña M, Heinrichs DE, Holdsworth DW, Gillies ER. Induction Heating Triggers Antibiotic Release and Synergistic Bacterial Killing on Polymer-Coated Titanium Surfaces. Adv Healthc Mater 2023; 12:e2202807. [PMID: 37053473 DOI: 10.1002/adhm.202202807] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 03/30/2023] [Indexed: 04/15/2023]
Abstract
Infection is a major complication associated with orthopedic implants. It often involves the development of biofilms on metal substrates, which act as barriers to the host's immune system and systemic antibiotic treatment. The current standard of treatment is revision surgery, often involving the delivery of antibiotics through incorporation into bone cements. However, these materials exhibit sub-optimal antibiotic release kinetics and revision surgeries have drawbacks of high cost and recovery time. Herein, a new approach is presented using induction heating of a metal substrate, combined with an antibiotic-loaded poly(ester amide) coating undergoing a glass transition just above physiological temperature to enable thermally triggered antibiotic release. At normal physiological temperature, the coating provides a rifampicin depot for >100 days, while heating of the coating accelerates drug release, with >20% release over a 1-h induction heating cycle. Induction heating or antibiotic-loaded coating alone each reduce Staphylococcus aureus (S. aureus) viability and biofilm formation on Ti, but the combination causes synergistic killing of S. aureus as measured by crystal violet staining, determination of bacterial viability (>99.9% reduction), and fluorescence microscopy of bacteria on surfaces. Overall, these materials provide a promising platform enabling externally triggered antibiotic release to prevent and/or treat bacterial colonization of implants.
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Affiliation(s)
- Jan C Kwan
- School of Biomedical Engineering, The University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 5B9, Canada
- Bone and Joint Institute, The University of Western Ontario, The Sandy Kirkley Centre for Musculoskeletal Research, University Hospital B6-200, London, Ontario, N6G 2V4, Canada
| | - Ronald S Flannagan
- Department of Microbiology and Immunology, The University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 5C1, Canada
| | - Mónica Vásquez Peña
- School of Biomedical Engineering, The University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 5B9, Canada
- Bone and Joint Institute, The University of Western Ontario, The Sandy Kirkley Centre for Musculoskeletal Research, University Hospital B6-200, London, Ontario, N6G 2V4, Canada
| | - David E Heinrichs
- Department of Microbiology and Immunology, The University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 5C1, Canada
| | - David W Holdsworth
- School of Biomedical Engineering, The University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 5B9, Canada
- Bone and Joint Institute, The University of Western Ontario, The Sandy Kirkley Centre for Musculoskeletal Research, University Hospital B6-200, London, Ontario, N6G 2V4, Canada
- Imaging Research Laboratories, Robarts Research Institute, The University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 2B8, Canada
- Department of Medical Biophysics, The University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 5C1, Canada
| | - Elizabeth R Gillies
- School of Biomedical Engineering, The University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 5B9, Canada
- Bone and Joint Institute, The University of Western Ontario, The Sandy Kirkley Centre for Musculoskeletal Research, University Hospital B6-200, London, Ontario, N6G 2V4, Canada
- Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 5B7, Canada
- Department of Chemical and Biochemical Engineering, The University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 5B9, Canada
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Physical Approaches to Prevent and Treat Bacterial Biofilm. Antibiotics (Basel) 2022; 12:antibiotics12010054. [PMID: 36671255 PMCID: PMC9854850 DOI: 10.3390/antibiotics12010054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Revised: 12/11/2022] [Accepted: 12/20/2022] [Indexed: 12/30/2022] Open
Abstract
Prosthetic joint infection (PJI) presents several clinical challenges. This is in large part due to the formation of biofilm which can make infection eradication exceedingly difficult. Following an extensive literature search, this review surveys a variety of non-pharmacological methods of preventing and/or treating biofilm within the body and how they could be utilized in the treatment of PJI. Special attention has been paid to physical strategies such as heat, light, sound, and electromagnetic energy, and their uses in biofilm treatment. Though these methods are still under study, they offer a potential means to reduce the morbidity and financial burden related to multiple stage revisions and prolonged systemic antibiotic courses that make up the current gold standard in PJI treatment. Given that these options are still in the early stages of development and offer their own strengths and weaknesses, this review offers an assessment of each method, the progress made on each, and allows for comparison of methods with discussion of future challenges to their implementation in a clinical setting.
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Pijls BG, Sanders IMJG, Kuijper EJ, Nelissen RGHH. Effectiveness of mechanical cleaning, antibiotics, and induction heating on eradication of Staphylococcus aureus in mature biofilms. Bone Joint Res 2022; 11:629-638. [PMID: 36047617 PMCID: PMC9533241 DOI: 10.1302/2046-3758.119.bjr-2022-0010.r1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Aims Here we used a mature seven-day biofilm model of Staphylococcus aureus, exposed to antibiotics up to an additional seven days, to establish the effectiveness of either mechanical cleaning or antibiotics or non-contact induction heating, and which combinations could eradicate S. aureus in mature biofilms. Methods Mature biofilms of S. aureus (ATCC 29213) were grown on titanium alloy (Ti6Al4V) coupons for seven days and were subjected to the following treatments or their combinations: antibiotics, mechanical cleaning, or heat shock by induction heating of 60°C for one minute. Experiments were repeated at least five times. Results In the untreated biofilm, growth up to 1.8×1011 colony-forming units (CFU)/cm2 was observed. Treatment with ciprofloxacin, flucloxacillin, vancomycin, cefuroxime, and amoxicillin all with rifampicin gave 6.0 log, 6.1 log, 1.4 log, 4.8 log, and 3.6 log reduction in CFU/cm2, respectively. Mechanical cleaning alone resulted in 4.9 log reduction and induction heating in 7.3 log reduction. There was an additional effect of ciprofloxacin, flucloxacillin, and induction heating when used in combinations. There was no additional effect for mechanical cleaning. No bacterial growth could be detected after induction heating followed by seven days of ciprofloxacin with rifampicin. Conclusion Mechanical cleaning, antibiotics, and non-contact induction heating reduced the bacterial load of mature S. aureus biofilms with approximately 5 log or more as a single treatment. The effect of mechanical cleaning on mature S. aureus biofilms was limited when used in combination with antibiotics and/or induction heating. Cite this article: Bone Joint Res 2022;11(9):629–638.
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Affiliation(s)
- B G Pijls
- Department of Orthopaedics, Leiden University Medical Center, Leiden, The Netherlands
| | - Ingrid M J G Sanders
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, The Netherlands
| | - Ed J Kuijper
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, The Netherlands
| | - R G H H Nelissen
- Department of Orthopaedics, Leiden University Medical Center, Leiden, The Netherlands
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Pijls BG, Sanders IMJG, Kuijper EJ, Nelissen RGHH. Synergy between induction heating, antibiotics, and N-acetylcysteine eradicates Staphylococcus aureus from biofilm. Int J Hyperthermia 2020; 37:130-136. [PMID: 31986930 DOI: 10.1080/02656736.2019.1710269] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Background: Non-contact induction heating (NCIH) is a noninvasive treatment modality that can be used to cause thermal damage to bacterial biofilms on a metal implant surface in the context of a prosthetic joint infection. The purpose of this study was (1) to determine the effectiveness of NCIH on killing Staphylococcus aureus from biofilm and (2) to determine the possible synergistic effect of NCIH and cocktails of antibiotics and N-acetylcysteine (NAC).Methods: Staphylococcus aureus biofilms were grown on titanium alloy (Ti6Al4V) coupons. These coupons were heated to 50 °C, 60 °C, 70 °C, 80 °C, and 90 °C for 3.5 min and subsequently exposed to cocktails of vancomycin, rifampicin and NAC at clinically relevant concentrations over 24 h.Results: In the control group without induction heating, 2.2*107 colony forming units (CFU)/cm2 were observed. At 50 °C, 60 °C, 70 °C, 80 °C, and 90 °C, a reduction of 0.3-log, 3.9-log, 4.2-log, 4.3-log, and 6.6-log CFU/cm2 were observed, respectively. There was synergy between antibiotics and induction heating that resulted in less than 100 CFU/cm2 remaining after 3.5 min at 60 °C, and exposure to vancomycin and rifampicin. Total eradication was observed at 80 °C. Total eradication was also observed at 60 °C and a cocktail of antibiotics with NAC.Conclusion: Induction heating of titanium alloy coupons is effective for the reduction of bacterial load in vitro in S. aureus biofilms. Induction heating and cocktails of antibiotics and NAC have a synergistic effect that results in the total eradication of the biofilm at 60 °C and higher for clinically relevant concentrations of vancomycin, rifampicin and NAC.
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Affiliation(s)
- Bart G Pijls
- Department of Orthopaedics, Leiden University Medical Center, Leiden, The Netherlands
| | - Ingrid M J G Sanders
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, The Netherlands
| | - Ed J Kuijper
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, The Netherlands
| | - Rob G H H Nelissen
- Department of Orthopaedics, Leiden University Medical Center, Leiden, The Netherlands
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Abstract
Aims Induction heating is a noninvasive, nonantibiotic treatment modality that can potentially be used to cause thermal damage to the bacterial biofilm on the metal implant surface. The purpose of this study was to determine the effectiveness of induction heating on killing Staphylococcus epidermidis from biofilm and to determine the possible synergistic effect of induction heating and antibiotics. Methods S. epidermidis biofilms were grown on titanium alloy (Ti6Al4V) coupons for 24 hours (young biofilm) and seven days (mature biofilm). These coupons with biofilm were heated to temperatures of 50°C, 55°C, 60°C, 65°C, 70°C, 80°C, and 90°C for 3.5 minutes and subsequently exposed to vancomycin and rifampicin at clinically relevant concentrations. Results For the young biofilm, total eradication was observed at 65°C or higher for 3.5 minutes followed by 24 hours of vancomycin 10 mg/l and rifampicin 1 mg/l. For the mature biofilm, total eradication was observed at 60°C for 3.5 minutes followed by 24 hours of vancomycin 10 mg/l and rifampicin 1 mg/l. Total eradication was also observed at 60°C for 3.5 minutes followed by 24 hours of vancomycin 1 mg/l and rifampicin 1 mg/l followed by another thermal shock of 60°C for 3.5 minutes (two thermal shocks). Conclusion Induction heating of Ti6Al4V coupons is effective in reducing bacterial load in vitro for S. epidermidis biofilms. Induction heating and antibiotics have a synergistic effect resulting in total eradication of the biofilm at 60°C or higher for clinically relevant concentrations of vancomycin and rifampicin. Cite this article:Bone Joint Res. 2020;9(4):192–199.
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Affiliation(s)
- Bart G Pijls
- Leiden University Medical Center, Leiden, The Netherlands
| | | | - Ed J Kujiper
- Leiden University Medical Center, Leiden, The Netherlands
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Contactless treatment for scoliosis by electromagnetically controlled shape-memory alloy rods: a preliminary study in rabbits. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2020; 29:1147-1158. [PMID: 32200495 DOI: 10.1007/s00586-019-06207-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 10/20/2019] [Accepted: 11/03/2019] [Indexed: 10/24/2022]
Abstract
PURPOSE To evaluate the safety and efficacy of a system aiming to correct scoliosis called "electromagnetically controlled shape-memory alloy rods" (EC-SMAR) used in a rabbit model. METHODS We heat-treated shape-memory alloy (SMA) rods to achieve a transition temperature between 34 and 47 °C and a C-shape austenite phase. We then developed a water-cooled generator capable of generating an alternating magnetic field (100 kHz) for induction heating. We next studied the efficacy of this system in vitro and determined some parameters prior to proceeding with animal experiments. We then employed a rabbit model, in which we fixed a straight rod along the spinous processes intraoperatively, and conducted induction heating postoperatively every 4 days for 1 month, while performing periodic X-ray assessments. RESULTS Significant kyphotic deformations with Cobb angles of about 45° (p < 0.01) were created in five rabbits, and no complications occurred throughout the experiment. The rabbits are still very much alive and do not show any signs of discomfort. CONCLUSIONS This is the first system that can modulate spinal deformation in a gradual, contactless, noninvasive manner through electromagnetic induction heating applied to SMA alloy rods. Although this study dealt with healthy spines, it provides promising evidence that this device also has the capacity to correct human kyphosis and even scoliosis in the future. These slides can be retrieved under Electronic Supplementary Material.
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Rosa N, Marta M, Vaz M, Tavares SMO, Simoes R, Magalhães FD, Marques AT. Intramedullary nailing biomechanics: Evolution and challenges. Proc Inst Mech Eng H 2019; 233:295-308. [DOI: 10.1177/0954411919827044] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
This article aims to review the biomechanical evolution of intramedullary nailing and describe the breakthrough concepts which allowed for nail improvement and its current success. The understanding of this field establishes an adequate background for forthcoming research and allows to infer on the path for future developments on intramedullary nailing. It was not until the 1940s, with the revolutionary Küntscher intramedullary nailing design, that this method was recognized as a widespread medical procedure. Such achievement was established based on the foundations created from intuition-based experiments and the first biomechanical ideologies. The nail evolved from allowing alignment and stability through press-fit fixation with nail-cortical wall friction to the nowadays nail stability achieved through interlocking screws mechanical linkage between nail and bone. Important landmarks during nail evolution comprise the introduction of flexible reaming, the progress from slotted to non-slotted nails design, the introduction of nail ‘dynamization’ and the use of titanium alloys as a new nail material. Current biomechanical improvement efforts aim to enhance the bone–intramedullary nail system stability. We suggested that benefit would be attained from a better understanding of the ideal mechano-biological environment at the fracture site, and future improvements will emerge from combining mechanics and biological tools.
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Affiliation(s)
- Natacha Rosa
- Department of Mechanical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
| | - Miguel Marta
- Department of Orthopaedics, Centro Hospitalar de São João, Porto, Portugal
| | - Mário Vaz
- Department of Mechanical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
- INEGI, Faculty of Engineering, University of Porto, Porto, Portugal
| | | | - Ricardo Simoes
- Polytechnic Institute of Cávado and Ave, Barcelos, Portugal
- Institute for Polymers and Composites IPC/I3N, University of Minho, Guimarães, Portugal
| | - Fernão D Magalhães
- LEPABE–Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, Portugal
| | - Antonio Torres Marques
- Department of Mechanical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
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Abstract
Objectives Prosthetic joint infection (PJI) is a devastating complication following total joint arthroplasty. Non-contact induction heating of metal implants is a new and emerging treatment for PJI. However, there may be concerns for potential tissue necrosis. It is thought that segmental induction heating can be used to control the thermal dose and to limit collateral thermal injury to the bone and surrounding tissues. The purpose of this study was to determine the thermal dose, for commonly used metal implants in orthopaedic surgery, at various distances from the heating centre (HC). Methods Commonly used metal orthopaedic implants (hip stem, intramedullary nail, and locking compression plate (LCP)) were heated segmentally using an induction heater. The thermal dose was expressed in cumulative equivalent minutes at 43°C (CEM43) and measured with a thermal camera at several different distances from the HC. A value of 16 CEM43 was used as the threshold for thermal damage in bone. Results Despite high thermal doses at the HC (7161 CEM43 to 66 640 CEM43), the thermal dose at various distances from the HC was lower than 16 CEM43 for the hip stem and nail. For the fracture plate without corresponding metal screws, doses higher than 16 CEM43 were measured up to 5 mm from the HC. Conclusion Segmental induction heating concentrates the thermal dose at the targeted metal implant areas and minimizes collateral thermal injury by using the non-heated metal as a heat sink. Implant type and geometry are important factors to consider, as they influence dissipation of heat and associated collateral thermal injury. Cite this article: B. G. Pijls, I. M. J. G. Sanders, E. J. Kuijper, R. G. H. H. Nelissen. Segmental induction heating of orthopaedic metal implants. Bone Joint Res 2018;7:609–619. DOI: 10.1302/2046-3758.711.BJR-2018-0080.R1.
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Affiliation(s)
- B G Pijls
- Department of Orthopaedics, Leiden University Medical Center, Leiden, The Netherlands
| | - I M J G Sanders
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, The Netherlands
| | - E J Kuijper
- Department of Medical Microbiology, Section Experimental Bacteriology, Leiden University Medical Center, Leiden, The Netherlands
| | - R G H H Nelissen
- Department of Orthopaedics, Leiden University Medical Center, Leiden, The Netherlands
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Krämer M, Müller CW, Hermann M, Decker S, Springer A, Overmeyer L, Hurschler C, Pfeifer R. Design considerations for a novel shape-memory-plate osteosynthesis allowing for non-invasive alteration of bending stiffness. J Mech Behav Biomed Mater 2017; 75:558-566. [PMID: 28858665 DOI: 10.1016/j.jmbbm.2017.08.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 07/10/2017] [Accepted: 08/21/2017] [Indexed: 11/18/2022]
Abstract
Biomechanical stimuli play a major role in fracture healing. Changing the fixation stiffness through the course of healing might accelerate bone healing and prevent healing complications. Shape memory alloy (SMA) based implants were developed to allow for non-invasive stiffness alteration during the fracture healing process. To gain a deeper understanding of the implant functionality based on the alloy characteristics and geometric design, the mechanical properties of different shape memory alloys where mechanically characterized. SMA bone plates were manufactured and the structural bending stiffness of the implants was determined at different temperatures and configurations. The temperature required for complete recovery of shape after deformation increased continuously with increasing pseudo-plastic deformation in SMA probes. Full recovery was observed at temperatures ranging from 38°C to 52°C after pseudo-plastic deformations ranging from 0.2% to 1.0% outer fibre strain, respectively. The small fragment inverse-dynamisation implants revealed bending stiffnesses ranging from 0.09Nm2 to 0.34Nm2 in the initial state and from 0.16Nm2 to 0.46Nm2 after shape alteration. Dependent on the design, a relative gain of the implant stiffness ranging from 18.8% to 115.0% could be observed. The large inverse-dynamisation implants revealed bending stiffnesses from 3.7Nm2 to 7.1Nm2 before and 4.1Nm2 to 12.6Nm2 after triggering the shape memory effect. Dependent on the design a gain in stiffness from 11.8% to 117.2% was observed. Warming the SMA implant to 40°C for a short period of time, leads to a moderate increase in implant stiffness of up to 64.5%, while triggering the implant with 50°C leads to a maximum increase in stiffness of up to 127.3%. The Nitinol shape memory bone plates have a huge potential for improving the treatment of long shaft fractures by allowing for the increase, decrease or incremental change of implant stiffness in fracture stabilization. However, the interaction between design, material properties, and manufacturing processes need to be carefully considered for each specific application to achieve optimum function of SMA-based, stiffness altering, fracture-fixation implants.
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Affiliation(s)
- Manuel Krämer
- Orthopaedic Department, Hannover Medical School (MHH), Anna-von Borries-Str. 1-7, 30625 Hannover, Germany.
| | - Christian W Müller
- Trauma Department, Hannover Medical School (MHH), Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Maike Hermann
- Orthopaedic Department, Hannover Medical School (MHH), Anna-von Borries-Str. 1-7, 30625 Hannover, Germany
| | - Sebastian Decker
- Trauma Department, Hannover Medical School (MHH), Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - André Springer
- Laser Zentrum Hannover e.V., Hollerithallee 8, 30419 Hannover, Germany
| | - Ludger Overmeyer
- Institute of Transport and Automation Technology, Leibniz University Hannover, An der Universität 2, 30823 Garbsen, Germany
| | - Christof Hurschler
- Orthopaedic Department, Hannover Medical School (MHH), Anna-von Borries-Str. 1-7, 30625 Hannover, Germany
| | - Ronny Pfeifer
- Laser Zentrum Hannover e.V., Hollerithallee 8, 30419 Hannover, Germany
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Pijls BG, Sanders IMJG, Kuijper EJ, Nelissen RGHH. Non-contact electromagnetic induction heating for eradicating bacteria and yeasts on biomaterials and possible relevance to orthopaedic implant infections: In vitro findings. Bone Joint Res 2017; 6:323-330. [PMID: 28522446 PMCID: PMC5457641 DOI: 10.1302/2046-3758.65.bjr-2016-0308.r1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 03/13/2017] [Indexed: 11/13/2022] Open
Abstract
Objectives Infection of implants is a major problem in elective and trauma surgery. Heating is an effective way to reduce the bacterial load in food preparation, and studies on hyperthermia treatment for cancer have shown that it is possible to heat metal objects with pulsed electromagnetic fields selectively (PEMF), also known as induction heating. We therefore set out to answer the following research question: is non-contact induction heating of metallic implants effective in reducing bacterial load in vitro? Methods Titanium alloy cylinders (Ti6Al4V) were exposed to PEMF from an induction heater with maximum 2000 watts at 27 kHz after being contaminated with five different types of micro-organisms: Staphylococcus epidermidis; Staphylococcus aureus; Pseudomonas aeruginosa; spore-forming Bacillus cereus; and yeast Candida albicans. The cylinders were exposed to incremental target temperatures (35°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C) for up to 3.5 minutes. Results There was an average linear heating rate of 0.39°C per second up to the target temperature, and thereafter the target temperature was maintained until the end of the experiment. At 60°C and higher (duration 3.5 minutes), there was a 6-log reduction or higher for every micro-organism tested. At 60°C, we found that the shortest duration of effective induction heating was 1.5 minutes. This resulted in a 5-log reduction or higher for every micro-organism tested. Conclusion Non-contact induction heating of a titanium disk is effective in reducing bacterial load in vitro. These promising results can be further explored as a new treatment modality for infections of metal orthopaedic implants. Cite this article: B. G. Pijls, I. M. J. G. Sanders, E. J. Kuijper, R. G. H. H. Nelissen. Non-contact electromagnetic induction heating for eradicating bacteria and yeasts on biomaterials and possible relevance to orthopaedic implant infections: In vitro findings. Bone Joint Res 2017;6:323–330. DOI: 10.1302/2046-3758.65.BJR-2016-0308.R1.
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Affiliation(s)
- B G Pijls
- Leiden University Medical Centre, Albinusdreef 2, P.O. Box 9600, Postzone J-11-S, 2300 RC Leiden, The Netherlands
| | - I M J G Sanders
- Leiden University Medical Centre, Albinusdreef 2, P.O. Box 9600, Postzone J-11-S, 2300 RC Leiden, The Netherlands
| | - E J Kuijper
- Leiden University Medical Centre, Albinusdreef 2, P.O. Box 9600, Postzone J-11-S, 2300 RC Leiden, The Netherlands
| | - R G H H Nelissen
- Leiden University Medical Centre, Albinusdreef 2, P.O. Box 9600, Postzone J-11-S, 2300 RC Leiden, The Netherlands
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A Novel Shape Memory Plate Osteosynthesis for Noninvasive Modulation of Fixation Stiffness in a Rabbit Tibia Osteotomy Model. BIOMED RESEARCH INTERNATIONAL 2015; 2015:652940. [PMID: 26167493 PMCID: PMC4475735 DOI: 10.1155/2015/652940] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Accepted: 05/30/2015] [Indexed: 01/09/2023]
Abstract
Nickel-titanium shape memory alloy (NiTi-SMA) implants might allow modulating fracture healing, changing their stiffness through alteration of both elastic modulus and cross-sectional shape by employing the shape memory effect (SME). Hypotheses: a novel NiTi-SMA plate stabilizes tibia osteotomies in rabbits. After noninvasive electromagnetic induction heating the alloy exhibits the SME and the plate changes towards higher stiffness (inverse dynamization) resulting in increased fixation stiffness and equal or better bony healing. In 14 rabbits, 1.0 mm tibia osteotomies were fixed with our experimental plate. Animals were randomised for control or induction heating at three weeks postoperatively. Repetitive X-ray imaging and in vivo measurements of bending stiffness were performed. After sacrifice at 8 weeks, macroscopic evaluation, µCT, and post mortem bending tests of the tibiae were carried out. One death and one early implant dislocation occurred. Following electromagnetic induction heating, radiographic and macroscopic changes of the implant proved successful SME activation. All osteotomies healed. In the treatment group, bending stiffness increased over time. Differences between groups were not significant. In conclusion, we demonstrated successful healing of rabbit tibia osteotomies using our novel NiTi-SMA plate. We demonstrated shape-changing SME in-vivo through transcutaneous electromagnetic induction heating. Thus, future orthopaedic implants could be modified without additional surgery.
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