Bio-Medical Materials and Engineering - Volume 25, issue 4

Authors: Mataliotakis, George I. | Tsouknidas, Alexander | Panteliou, Sofia | Vekris, Marios D. | Mitsionis, Grigorios I. | Agathopoulos, Simeon | Beris, Alexander E.

Article Type: Research Article

Abstract: BACKGROUND: The optimum fixation device for the critical size bone defect is not established yet. OBJECTIVE: A reliable, feasible and low-cost fixation device for the long-term maintenance of a critical bone defect. METHODS: A custom-made plate made of poly-methyl-methacrylate was used for the fixation of a critical defect of rats’ femurs. The screws were securely fixing both on the plate and the bone. A three point bending test, aimed to resemble the in vivo loading pattern, a Finite Element Analysis and a 24-week in vivo monitoring of the integrity of the plate fixation …were utilized. RESULTS: The plate has linear and reproducible behavior. It presents no discontinuities in the stress field of the fixation. Its properties are attributed to the material and the locking principle. It fails beyond the level of magnitude of the normal ambulatory loads. In vivo , 100% of the plates maintained the bone defect intact up to 12 weeks and 85% of them at 24 weeks. CONCLUSION: This novel locking plate shows optimal biomechanical performance and reliability with high long-term in vivo survival rate. It is fully implantable, inexpensive and easily manufactured. It can be qualified for long term critical defect fixation in bone regeneration studies. Show more

Keywords: Bone tissue engineering, segmental bone defects, animal models, plate, critical size defect, fixation device

DOI: 10.3233/BME-151540

Citation: Bio-Medical Materials and Engineering, vol. 25, no. 4, pp. 335-346, 2015

Authors: Thuaksuban, Nuttawut | Nuntanaranont, Thongchai | Suttapreyasri, Srisurang | Boonyaphiphat, Pleumjit

Article Type: Research Article

Abstract: The ability to repair bone defects of polycaprolactone–chitosan scaffolds containing 20% chitosan (PCL-20%CS) fabricated using the melt stretching and multilayer deposition (MSMD) technique was assessed and compared with commercial scaffolds. Two calvarium defects of 11 mm in diameter were created in each of the fifteen New Zealand white rabbits. The PCL-20%CS scaffolds were implanted in one site (group A) while another site was performed with PCL–tricalcium phosphate (TCP) scaffolds containing 20% TCP (PCL-20%TCP) fabricated by fused deposition modeling technique (FDM) (group B). At two, four and eight weeks thereafter, new bone regeneration within the defects was assessed using histomorphometric and micro-computed …tomography (µ-CT) analysis. The result of histological sections demonstrated that chronic inflammatory reaction was generally detected along scaffolds of group A, but it was not found in group B. Over 8 weeks, the µ-CT analysis indicated that the average amount of new bone of group A was slightly less than that of group B (p > 0.05 ). In conclusion, efficacy of the PCL-20%CS MSMD scaffolds for repairing bone defects was less than that of the PCL-20%TCP FDM scaffolds. However, MSMD scaffolding is still the technique of choice, but needed some modifications. Show more

Keywords: Polycaprolactone, chitosan, scaffold, calvarium

DOI: 10.3233/BME-151539

Citation: Bio-Medical Materials and Engineering, vol. 25, no. 4, pp. 347-360, 2015

Authors: Yamashita, Keigo | Suzuki, Shuko | Tabayashi, Nobuoki | Abe, Takehisa | Hayata, Yoshihiro | Hirose, Tomoaki | Hiraga, Shun | Niwa, Kosuke | Fukuba, Ryohei | Takeda, Maiko | Ikada, Yoshito | Taniguchi, Shigeki

Article Type: Research Article

Abstract: BACKGROUND: Anastomotic needle hole bleeding is a frequently encountered problem in cardiovascular surgeries. OBJECTIVE: To examine the feasibility of crosslinked gelatin glue as an anastomotic needle hole sealant in comparison with fibrin glue. METHODS: The in vitro burst water pressures were measured for gelatin and fibrin glue sealed needle holes of expanded polytetrafluoroethylene (ePTFE) or collagen coated woven polyester grafts. For in vivo investigations, abdominal aorta-ePTFE graft anastomoses of heparinized beagle dogs were sealed by gelatin or fibrin glue and hemostatic efficacy was judged. The implanted sites were re-examined 4 weeks postoperatively. …RESULTS: The in vitro burst water pressures of gelatin glue sealed needle holes of both grafts were higher than those sealed by fibrin glue. For in vivo canine studies, hemostasis was successful for all gelatin glue applied suture lines, but not two out of three fibrin glue treated sites when 3-0 polypropylene suture was employed. Although adhesions of surrounding tissues were intense for all sites 4 weeks postoperatively, inflammation was more severe for the fibrin glue group compared to those of gelatin glue. CONCLUSIONS: Gelatin glue was found to be an effective and safe sealant for accomplishing hemostasis of anastomotic needle holes of vascular grafts. Show more

Keywords: Gelatin, sealant, fibrin glue, needle hole hemostasis

DOI: 10.3233/BME-151534

Citation: Bio-Medical Materials and Engineering, vol. 25, no. 4, pp. 361-370, 2015

Authors: Sano, Hirotaka | Imagawa, Kei | Yamamoto, Nobuyuki | Ozawa, Hiroshi | Yokobori Jr., A. Toshimitsu | Itoi, Eiji

Article Type: Research Article

Abstract: BACKGROUND: Failure of inserted anchors has been recognized as one of the major pathomechanisms of re-tearing after rotator cuff repair. OBJECTIVE: To predict the inserted anchor failure using CT-based 3-dimensional finite element method (CT/3D-FEM). METHODS: Among twenty patients who underwent rotator cuff repair, 5 had anchor failure (failed anchor group) and 15 had no anchor failure (stable anchor group). A 3D model of proximal humerus was developed for each patient based on the CT data. A virtual pullout testing of TWINFIX™ anchors inserted into bone at 6 different sites was performed using FEM. Then, mean …failure load of 6 anchors for each patient was compared between two groups. Moreover, an optimal cut-off value of the mean failure load was determined for predicting anchor failure. RESULTS: The mean failure load in the failed anchor group (70.3 N) was significantly lower than that in the stable anchor group (119.0 N; p < 0.0001 ). In our method, the optimum cut-off value of the mean failure load was 75.4 N. CONCLUSIONS: Failure of the inserted TWINFIX™ anchor could be predicted using CT/3D-FEM. In this method, there seemed to be a high risk of anchor failure in shoulders with a mean failure load of <75.4 N. Show more

Keywords: Rotator cuff repair, suture anchor, pullout strength, computed tomography, finite element method

DOI: 10.3233/BME-151535

Citation: Bio-Medical Materials and Engineering, vol. 25, no. 4, pp. 371-380, 2015

Authors: Fermor, H.L. | McLure, S.W.D. | Taylor, S.D. | Russell, S.L. | Williams, S. | Fisher, J. | Ingham, E.

Article Type: Research Article

Abstract: This study aimed to determine the optimal starting material for the development of an acellular osteochondral graft. Osteochondral tissues from three different species were characterised; pig (6 months), cow (18 months) and two ages of sheep (8–12 months and >4 year old). Tissues from the acetabulum and femoral head of the hip, and the groove, medial and lateral condyles and tibial plateau of the knee were assessed. Histological analysis of each tissue allowed for qualification of cartilage histoarchitecture, glycosaminoglycan (GAG) distribution, assessment of cellularity and cartilage thickness. Collagen and GAG content were quantified and cartilage water content was defined. Following biomechanical testing, the …percentage deformation, permeability and equilibrium elastic modulus was determined. Results showed that porcine cartilage had the highest concentration of sulphated proteoglycans and that the condyles and groove of the knee showed higher GAG content than other joint areas. Cartilage from younger tissues (porcine and young ovine) had higher cell content and was thicker, reflecting the effects of age on cartilage structure. Cartilage from older sheep had a much higher elastic modulus and was less permeable than other species. Show more

Keywords: Cartilage, glycosaminoglycan, collagen, thickness, water content, cellularity, percentage deformation, permeability, equilibrium elastic modulus

DOI: 10.3233/BME-151533

Citation: Bio-Medical Materials and Engineering, vol. 25, no. 4, pp. 381-395, 2015

Authors: Mardas, Marcin | Kubisz, Leszek | Biskupski, Piotr | Mielcarek, Sławomir

Article Type: Research Article

Abstract: The increased use of allograft tissue for musculoskeletal repair has brought more focus to the safety of allogenic tissue and the efficacy of various sterilization techniques. The currently available literature contains few examples of studies on long-lasting strains of bones but no example for irradiated bones. In this study the bovine femurs from a 2-year-old animal were machine cut and irradiated with the doses of 10, 15, 25, 35, 45 and 50 kGy. The dynamic mechanical analysis was performed at 1 Hz at the room temperature in a 3-point bending configuration for 2880 minutes. The final values of E ′ …and E ″ were dose independent but they were reached at different periods. For this reason, so called “critical point” was introduced for the further analysis. All the examined sample groups were characterized by statistically significant lower values of the critical point in comparison with the control samples (p < 0.05 ) but the biggest differences were observed between the control samples and the samples irradiated with the doses of 10, 15 and 25 kGy. Current results and literature review suggest that the dose of 35 kGy is the optimal dose for ionizing radiation sterilization. Show more

Keywords: Bone, radiation, sterilization, DMA (Dynamic Mechanical Analysis)

DOI: 10.3233/BME-151536

Citation: Bio-Medical Materials and Engineering, vol. 25, no. 4, pp. 397-403, 2015

Authors: Sun, Ziling | Zhou, Yang | Zhou, Jiawang

Article Type: Research Article

Abstract: Porous silk fibroin films can provide an optimal microenvironment for angiogenesis in vivo . Adhesion and migration of human umbilical vein endothelial cells (HUVEC) on porous silk films were observed by confocal laser scanning microscopy. The expression of fibronectin (FN), laminins (LN), intercellular adhesion molecule-l (ICAM-1) and vascular cell adhesion molecule-l (VCAM-1) after implanting Porous Silk Fibroin Films (PSFFs) as grafts for dermis regeneration in rat were studied. FN, LN, ICAM and VCAM may have direct relationships with angiogenesis. The result will help to design excellent PSFFs and study the process and mechanism of angiogenesis.

Keywords: Angiogenesis, HUVEC, PSFFs, FN, LN

DOI: 10.3233/BME-151541

Citation: Bio-Medical Materials and Engineering, vol. 25, no. 4, pp. 405-413, 2015

Authors: Mahomed, Aziza | Hukins, David W.L. | Kukureka, Stephen N.

Article Type: Research Article

Abstract: The viscoelastic properties of cylinders (diameter 5 mm, height 2.2 ± 0.2 mm) of Nagor silicone elastomer of medium hardness, were investigated before and after the specimens had undergone accelerated aging in saline solution at 70°C for 38, 76 and 114 days (to simulate aging at 37°C, for 1, 2 and 3 years, respectively). All sets of specimens were immersed in physiological saline solution at 37°C during testing and the properties were measured using dynamic mechanical analysis (DMA). A sinusoidal cyclic compression of 40 N ± 5 N was applied over a frequency range, f , of 0.02–25 Hz. Values of the storage, E ′ …, and loss, E ″ , moduli were found to depend on f ; the dependence of E ′ or E ″ on the logarithm (base 10) of f was represented by a second-order polynomial. After accelerated aging, the E ′ and E ″ values did not increase significantly (p < 0.05 ). Furthermore, scanning electron microscopy (SEM) showed that accelerated aging did not affect the surface morphology of silicone. Attenuated total reflectance Fourier transform infra-red spectroscopy (ATR-FTIR) showed that accelerated aging had a negligible effect on the surface chemical structures of the material. Differential scanning calorimetry (DSC) showed no changes to the bulk properties of silicone, following accelerated aging. Show more

Keywords: Accelerated aging, compression, dynamic mechanical analysis (DMA), silicone, viscoelasticity

DOI: 10.3233/BME-151538

Citation: Bio-Medical Materials and Engineering, vol. 25, no. 4, pp. 415-423, 2015

Authors: Tsouknidas, Alexander

Article Type: Research Article

Abstract: BACKGROUND: The increasing prevalence of spine disorders in industrialized environments has impaired the quality of life in the elder population. In an effort to relieve pain, physicians strive to improve treatment through the consideration of patient specific characteristics during preoperative planning of procedures such as spinal fusion. OBJECTIVE: This study aims at quantifying aspects of spondylodesis to the loading and mobility of the utilized instrumentation, as the use of rigid vs. motion sparing materials as well as implantation angle and depth of the pedicle screws are still subject to controversy among surgeons. METHODS: A fixation …assembly was reverse engineered based on µCT measurements of the involved instrumentation. Two pedicle screws were connected with a rod, thus representing a mono-segmental fixation device. The pedicle screws were embedded in hexahedral structures simulated by bone properties. Upon validation and verification, the response of the model to a compressive and a torsional load was simulated in ANSYS 14, while altering the implantation depth and insertion angle of the pedicle screws along with the rod material. RESULTS: The mobility of the instrumentation was drastically increased (by up to 390%) when PEEK rods were used in place of traditional Ti ones, a tendency observed at varying extent for all simulated scenarios. Shallow implantation induced a slight stress increase (∼21%) on the implant and a notable distressing of the bony tissue (∼44%), whereas inclined screw positioning was overall beneficial to the developing stress fields in both, with bone profiting a max. stress release of ∼15% during the application of torsion. CONCLUSIONS: The investigation presented refined insight into the biomechanical response of a spinal fusion device. As expected, rigid fixation seems preferable in fusion oriented instrumentation whereas semi rigid devices should be employed for non-fusion applications. Shallow implantation resulted in a slight posterior offset of the stabilization device, which could be beneficial in the treatment of osteoporotic patients. Show more

Keywords: Spine fusion, load transition, stiffness, implantation

DOI: 10.3233/BME-151537

Citation: Bio-Medical Materials and Engineering, vol. 25, no. 4, pp. 425-433, 2015

Authors: Wu, Tao | Chen, Xiao | Fan, Dezeng | Pang, Xiaolu

Article Type: Research Article

Abstract: BACKGROUND: With life pace accelerated, poor diet habits developed, psychological burden enhanced and many other factors, the incidence of coronary heart disease, atherosclerosis and other cardiovascular cerebrovascular diseases has been increased year by year, which are serious threat to human health. OBJECTIVE: Provide relational references for the similar researchers after metal stent materials were reviewed and prospected. METHODS: This paper reviews the development and application of metal materials in terms of vascular stents, focusing on the advantages and disadvantages of 316L stainless steel, nitinol super-elastic alloys, cobalt-based alloys (Co–Cr–Ni–Mo–Mn), magnesium-based alloy, iron-based alloys and tantalum …metal stents as well as in clinical practice research and application. RESULTS: Recognize the advantages and disadvantages of different metal stent materials as well as in clinical practice research and application. CONCLUSIONS: Although metal stents have been widely used in clinical practice, there are still many problems to be solved, especially to improve mechanical properties and biological activity. Strong immune rejection is also a problem. Therefore, it will be a significant direction for future material research to treat surface modification, further improve the biocompatibility, reduce the thrombosis and completely eliminate the rejection and vascular restenosis. In addition, the stent materials should be developed toward controllable degradation and special features in the future. Show more

Keywords: Vascular stents, metal materials, development, application

DOI: 10.3233/BME-151542

Citation: Bio-Medical Materials and Engineering, vol. 25, no. 4, pp. 435-441, 2015