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Vieira AFC, Da Silva EHP, Ribeiro ML. Numerical Approach to Simulate the Mechanical Behavior of Biodegradable Polymers during Erosion. Polymers (Basel) 2023; 15:polym15091979. [PMID: 37177128 PMCID: PMC10181274 DOI: 10.3390/polym15091979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 03/31/2023] [Accepted: 04/18/2023] [Indexed: 05/15/2023] Open
Abstract
Biodegradable polymers find applications in many market segments. The ability to meet mechanical requirements within a certain time range, after which it degrades and is naturally absorbed, can be used to produce short-term use products that can be easily disposable with less environmental impact. In the segment of medical devices used in regenerative medicine, these materials are used to produce temporary implants that are naturally assimilated by the human body, avoiding a removal surgery. However, the design of these temporary devices still presents great challenges, namely in the verification of the main requirement: the lifetime of the device, associated with the progressive loss of mechanical properties, until its complete erosion and assimilation. Thus, in this study, a numerical approach is proposed to simulate the polymeric device's mechanical behavior during its hydrolytic degradation by combining the hydrolysis kinetics, that depends on mechanical factors and promotes a decrease of molecular weight and consequent decrease of mechanical performance, and erosion, when molecular weight reaches a threshold value and the polymer becomes soluble and diffuses outward, resulting in mass loss and decreasing cross-sectional area, which also contributes to the mechanical performance reduction of the device. A phenomenological approach, using the combination of continuum-based hydrolytic damage for the evolution of mechanical properties that depends on the stress field and further removal of the degraded element (to simulate mass loss) was used. Both elastoplastic and hyperelastic constitutive models were applied on this study, where the material model parameters locally depend on the molecular weight.
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Affiliation(s)
- André F C Vieira
- Center for Mechanical and Aerospace Science and Technologies (C-MAST-UBI), Universidade da Beira Interior, R. Marquês D'Ávila e Bolama, 6201-001 Covilhã, Portugal
| | - Enio H P Da Silva
- Aeronautical Engineering Department, São Carlos School of Engineering, University of São Paulo, São Carlos 13563-120, SP, Brazil
| | - Marcelo L Ribeiro
- Aeronautical Engineering Department, São Carlos School of Engineering, University of São Paulo, São Carlos 13563-120, SP, Brazil
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2
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Wittawat R, Rittipun R, Nattaporn B. Development of
PLA
/
EPDM
/
SiO
2
blended polymer for biodegradable packaging. J Appl Polym Sci 2022. [DOI: 10.1002/app.53239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
| | - Rungruang Rittipun
- Faculty of Science and Technology Suan Dusit University Bangkok Thailand
| | - Boohuad Nattaporn
- Faculty of Science and Technology Suan Dusit University Bangkok Thailand
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3
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Sun X, Chen L, Wang R, Jiang M, Sun M, Liang W. Control of hydrolytic degradation of polyglycolic acid using chain extender and anti‐hydrolysis agent. J Appl Polym Sci 2022. [DOI: 10.1002/app.52398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Xiaojie Sun
- National Institute of Clean and Low‐Carbon Energy Beijing China
| | - Lanlan Chen
- National Institute of Clean and Low‐Carbon Energy Beijing China
| | - Rong Wang
- National Institute of Clean and Low‐Carbon Energy Beijing China
| | - Meng Jiang
- National Institute of Clean and Low‐Carbon Energy Beijing China
| | - Miaomiao Sun
- National Institute of Clean and Low‐Carbon Energy Beijing China
| | - Wenbin Liang
- National Institute of Clean and Low‐Carbon Energy Beijing China
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4
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Ishigaki K, Höglund OV, Asano K. Resorbable self-locking device for canine lung lobectomy: A clinical and experimental study. Vet Surg 2021; 50 Suppl 1:O32-O39. [PMID: 33687090 DOI: 10.1111/vsu.13623] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 02/21/2021] [Accepted: 02/25/2021] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To test the feasibility of a resorbable self-locking device for sealing of lung tissue in lung lobectomy in experimental dogs and dogs with pulmonary mass, and to study its resorption with CT. STUDY DESIGN Experimental study and clinical case series. ANIMALS Five beagles in the experimental group; six canine patients with a pulmonary mass in the clinical group. METHODS In both groups, an intercostal incision into thorax was performed. A resorbable self-locking device, LigaTie, was applied at the hilum of left cranial lobe in the experimental group and the affected lobe in the clinical group. Each lobe was removed by cutting the tissue just distal to the device. Video-assisted thoracic surgery was used in the experimental group; postoperative diagnostic imaging was repeated monthly until the device was not apparent on CT. RESULTS Application of LigaTie was feasible for lung lobectomy in all dogs. The device enabled en bloc ligation of the hilum of the affected lobe including the pulmonary arteries and veins and lobular bronchus. No air leakage from the resection stump was observed in any dog. Trace of the device on CT images gradually decreased and was undetectable at 4 months postoperatively in experimental dogs. CONCLUSION This study suggested that the resorbable self-locking device may be used for sealing of airways in complete lung lobectomy. CLINICAL RELEVANCE The resorbable self-locking device is suggested to be useful for canine lung lobectomy and may facilitate thoracoscopic lung lobectomy. Further investigations on its clinical application in small animal surgery are warranted.
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Affiliation(s)
- Kumiko Ishigaki
- Department of Veterinary Medicine, College of Bioresource Sciences, Nihon University, Fujisawa, Japan
| | - Odd Viking Höglund
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Kazushi Asano
- Department of Veterinary Medicine, College of Bioresource Sciences, Nihon University, Fujisawa, Japan
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5
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Polak-Kraśna K, Abaei AR, Shirazi RN, Parle E, Carroll O, Ronan W, Vaughan TJ. Physical and mechanical degradation behaviour of semi-crystalline PLLA for bioresorbable stent applications. J Mech Behav Biomed Mater 2021; 118:104409. [PMID: 33836301 DOI: 10.1016/j.jmbbm.2021.104409] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 01/07/2021] [Accepted: 02/13/2021] [Indexed: 11/19/2022]
Abstract
This study presents a systematic evaluation of the physical, thermal and mechanical performance of medical-grade semi-crystalline PLLA undergoing thermally-accelerated degradation. Samples were immersed in phosphate-buffered saline solution at 50 °C for 112 days and mass loss, molecular weight, thermal properties, degree of crystallinity, FTIR and Raman spectra, tensile elastic modulus, yield stress and failure stress/strain were evaluated at consecutive time points. Samples showed a consistent reduction in molecular weight and melting temperature, a consistent increase in percent crystallinity and limited changes in glass transition temperature and mass loss. At day 49, a drastic reduction in tensile failure strain was observed, despite the fact that elastic modulus, yield and tensile strength of samples were maintained. Brittleness increase was followed by rapid increase in degradation rate. Beyond day 70, samples became too brittle to test indicating substantial deterioration of their load-bearing capacity. This study also presents a computational micromechanics framework that demonstrates that the elastic modulus of a semi-crystalline polymer undergoing degradation can be maintained, despite a reducing molecular weight through compensatory increases in percent crystallinity. This study presents novel insight into the relationship between physical properties and mechanical performance of medical-grade PLLA during degradation and could have important implications for design and development of bioresorbable stents for vascular applications.
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Affiliation(s)
- Katarzyna Polak-Kraśna
- Biomechanics Research Centre (BioMEC), Biomedical Engineering, School of Engineering, College of Science and Engineering, National University of Ireland Galway, Galway, Ireland.
| | - Ali Reza Abaei
- Biomechanics Research Centre (BioMEC), Biomedical Engineering, School of Engineering, College of Science and Engineering, National University of Ireland Galway, Galway, Ireland
| | - Reyhaneh Neghabat Shirazi
- Biomechanics Research Centre (BioMEC), Biomedical Engineering, School of Engineering, College of Science and Engineering, National University of Ireland Galway, Galway, Ireland
| | - Eoin Parle
- Biomechanics Research Centre (BioMEC), Biomedical Engineering, School of Engineering, College of Science and Engineering, National University of Ireland Galway, Galway, Ireland
| | - Oliver Carroll
- CÚRAM, Centre for Research in Medical Devices, Biomedical Sciences, National University of Ireland Galway, Galway, Ireland
| | - William Ronan
- Biomechanics Research Centre (BioMEC), Biomedical Engineering, School of Engineering, College of Science and Engineering, National University of Ireland Galway, Galway, Ireland
| | - Ted J Vaughan
- Biomechanics Research Centre (BioMEC), Biomedical Engineering, School of Engineering, College of Science and Engineering, National University of Ireland Galway, Galway, Ireland.
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6
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Ekinci A, Gleadall A, Johnson AA, Li L, Han X. Mechanical and hydrolytic properties of thin polylactic acid films by fused filament fabrication. J Mech Behav Biomed Mater 2020; 114:104217. [PMID: 33246876 DOI: 10.1016/j.jmbbm.2020.104217] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 10/26/2020] [Accepted: 11/15/2020] [Indexed: 01/14/2023]
Abstract
Thin polymeric films are widely used as medical applications such as cell culture, stent, drug delivery and mechanical fixation. One of the most commonly used materials is polylactic acid (PLA) - a material, which is non-toxic, biodegradable and biocompatible. Fused filament fabrication (FFF) is a preferable additive manufacturing technique to manufacture polymers, where PLA is one of the most common materials. FFF is a promising technique for customised biomedical applications due to its relatively low cost and geometrical flexibility where biomedical applications are patient tailored. This study is the first to consider FFF monolayered thin films of PLA in terms of mechanical and hydrolytic properties at 37 °C in vitro degradation. Throughout degradation, the reduction in mechanical properties was examined by analysing molecular weight and thermal properties. FFF monolayered PLA underwent autocatalytic bulk degradation with no proof of significant mass loss. Young's modulus, ultimate tensile strength and molecular weight reduced by approximately 60%, 86%, and 80% after 280 days, respectively, while the degree of crystallinity increased by 143% in comparison to benchmark thin films at day 0. It was found that the decrease in mechanical properties was more sensitive to the increase in crystallinity in the early stage of the degradation, while the molecular weight was more dominant in the late stage of the degradation. This study provides practical information in terms of mechanical properties to support medical device designers in a range of potential end-use biomedical applications to achieve safe functional products over the required degradation lifetime.
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Affiliation(s)
- Alper Ekinci
- Wolfson School of Mechanical, Electrical and Manufacturing Engineering, Loughborough University, Loughborough, LE11 3TU, UK
| | - Andy Gleadall
- Wolfson School of Mechanical, Electrical and Manufacturing Engineering, Loughborough University, Loughborough, LE11 3TU, UK
| | - Andrew A Johnson
- School of Design & Creative Arts, Loughborough University, Loughborough, LE11 3TU, UK
| | - Ling Li
- State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, 410082, China
| | - Xiaoxiao Han
- State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, 410082, China.
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7
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Taguti MVH, Françoso A, Ribeiro ML, Vieira AFC. Numerical approach to simulate the mechanical behavior of biodegradable structures considering degradation time and heterogeneous stress field. POLYM ENG SCI 2020. [DOI: 10.1002/pen.25402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | - Adriano Françoso
- São Carlos School of EngineeringUniversity São Paulo São Paulo Brazil
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8
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Amnael Orozco-Díaz C, Moorehead R, Reilly GC, Gilchrist F, Miller C. Characterization of a composite polylactic acid-hydroxyapatite 3D-printing filament for bone-regeneration. Biomed Phys Eng Express 2020; 6:025007. [PMID: 33438633 DOI: 10.1088/2057-1976/ab73f8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Autologous cancellous-bone grafts are the current gold standard for therapeutic interventions in which bone-regeneration is desired. The main limitations of these implants are the need for a secondary surgical site, creating a wound on the patient, the limited availability of harvest-safe bone, and the lack of structural integrity of the grafts. Synthetic, resorbable, bone-regeneration materials could pose a viable treatment alternative, that could be implemented through 3D-printing. We present here the development of a polylactic acid-hydroxyapatite (PLA-HAp) composite that can be processed through a commercial-grade 3D-printer. We have shown that this material could be a viable option for the development of therapeutic implants for bone regeneration. Biocompatibility in vitro was demonstrated through cell viability studies using the osteoblastic MG63 cell-line, and we have also provided evidence that the presence of HAp in the polymer matrix enhances cell attachment and osteogenicity of the material. We have also provided guidelines for the optimal PLA-HAp ratio for this application, as well as further characterisation of the mechanical and thermal properties of the composite. This study encompasses the base for further research on the possibilities and safety of 3D-printable, polymer-based, resorbable composites for bone regeneration.
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Affiliation(s)
- C Amnael Orozco-Díaz
- School of Clinical Dentistry, University of Sheffield, Sheffield, United Kingdom
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9
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Haim Zada M, Kumar A, Elmalak O, Mechrez G, Domb AJ. Effect of Ethylene Oxide and Gamma (γ-) Sterilization on the Properties of a PLCL Polymer Material in Balloon Implants. ACS OMEGA 2019; 4:21319-21326. [PMID: 31867526 PMCID: PMC6921626 DOI: 10.1021/acsomega.9b02889] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 11/19/2019] [Indexed: 06/10/2023]
Abstract
Poly-l-lactide-co-ε-caprolactone (PLCL) is a unique polymer containing both polylactic acid and poly-ε-caprolactone (PCL) chain units, and thus it has better flexible and biodegradable properties. Based on these unique properties of PLCL, we have developed balloons that are now widely used in treating major medical problems [Biomaterials 2016, 105, 109-116]. One of the most important considerations needed for balloons is to ensure that the material properties remain similar after undergoing ethylene oxide (EtO) or gamma (γ-) sterilization treatments. From the biotechnological point of view, we focused on analyzing the vital molecular properties of the PLCL material after sterilization, such as changes in crystallinity, molecular weight distributions (M w, M n, and polydispersity index), and inherent viscosity (η). Analysis of the data reveals that EtO sterilization does not engender any change in crystallinity, melting temperature (T m), molecular weights, and η of the polymer. On the contrary, γ-radiations induce chain scission and consequential decrease of ∼33 and ∼15% in molecular weights and η values, respectively. Based on our observations, we recommend EtO sterilization instead of γ-radiation for PLCL. This ensures prolonged stability of the polymer against degradation in a biological environment, long-shelf life, and absolute assurance that balloon failures do not occur after implantation.
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Affiliation(s)
- Moran Haim Zada
- Institute
of Drug Research, Alex Grass Center for Drug Design and Novel Therapeutics,
School of Pharmacy-Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Awanish Kumar
- Institute
of Drug Research, Alex Grass Center for Drug Design and Novel Therapeutics,
School of Pharmacy-Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Omar Elmalak
- Institute
of Drug Research, Alex Grass Center for Drug Design and Novel Therapeutics,
School of Pharmacy-Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Guy Mechrez
- Department
of Food Quality and Safety, Institute for Postharvest and Food Sciences,
Volcani Center, ARO, 68 HaMaccabim Road, Rishon
LeZion 7505101, Israel
| | - Abraham J. Domb
- Institute
of Drug Research, Alex Grass Center for Drug Design and Novel Therapeutics,
School of Pharmacy-Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
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10
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Ro K, Rhee SM, Kim JY, Kim MS, Kim JD, Lee H, Rhee YG. All-Suture Anchor Settling After Arthroscopic Repair of Small and Medium Rotator Cuff Tears. Am J Sports Med 2019; 47:3483-3490. [PMID: 31718248 DOI: 10.1177/0363546519886547] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND All-suture anchors are increasingly being used in rotator cuff repair. However, there are debates on the micromotion of all-suture anchors. PURPOSE To perform rotator cuff repair on patients with rotator cuff tears and different shoulder bone mineral densities (BMDs) and investigate (1) where the anchor is located under the cortex, (2) if there is any anchor migration settling during follow-up, and (3) if structural outcome differs according to shoulder BMD. STUDY DESIGN Cohort study; Level of evidence, 3. METHODS We retrospectively investigated 88 patients who underwent arthroscopic single-row repair for small- to medium-sized rotator cuff tears (age [mean ± SD], 58.8 ± 7.1 years) from 712 cases of rotator cuff tendon repair between November 2015 and February 2018. Inclusion criteria were as follows: use of an all-suture anchor; preoperative shoulder BMD; and magnetic resonance imaging (MRI) conducted preoperatively, 2 days after surgery, and 10 months after surgery. Patients were excluded from the study if they underwent open rotator cuff repair (n = 118), got surgery with a double-row technique (n = 178), underwent surgery with anchors other than the all-suture type (n = 273), received anchor insertion in sites other than the greater tuberosity owing to concomitant procedures such as biceps tenodesis and subscapularis repair (n = 29), did not take preoperative shoulder BMD (n = 15), had more than a large-size tear (n = 6), and were lost to follow-up (n = 5). After compression of the all-suture anchor during surgery, the strands were pulled multiple times to ensure that the anchor was fixed onto the bone with appropriate tension. BMD was measured before surgery. Depth to anchor (DA), anchor settling, and repaired rotator cuff integrity were measured with MRI. Patients were categorized into 3 groups: group A (BMD, <0.4 g/cm2; n = 31), group B (BMD, 0.4-0.6 g/cm2; n = 32), and group C (BMD, >0.6 g/cm2; n = 25). A total of 65 patients had follow-up MRI. On the basis of rotator cuff tendon integrity, patients were categorized into either a sufficient thickness group (group S, Sugaya classification grade II or lower; n = 44) or an insufficient thickness group (group I, Sugaya classification grade III or higher; n = 21). RESULTS On time-zero MRI, the DA differed significantly among groups (group A, 3.62 ± 2.02 mm; group B, 5.18 ± 2.13 mm; group C, 6.30 ± 3.34 mm) (P = .001). The DA was deeper in patients with a higher BMD at time zero (r = 0.374; P = .001), but the DA did not differ at follow-up MRI (mean, 10.3 months after surgery). On follow-up MRI, anchor settling tended to increase with deeper time-zero DA (r = 0.769; P < .001). Anchor settling was significantly different among groups (group A, 1.33 ± 1.08 mm; group B, 2.78 ± 1.99 mm; group C, 3.81 ± 2.19 mm) (P = .001). The proportion of patients with sufficient thickness in each group did not show a statistical difference (group A, 70.8%; group B, 72.7%; group C, 57.9%) (P = .550). CONCLUSION In conclusion, this study confirmed that the postoperative site of anchor insertion in arthroscopic single-row rotator cuff repair with all-suture anchors was located farther from the cortex in patients with higher shoulder BMD and closer to the subcortical bone in patients with lower BMD. On follow-up MRI, no further settling occurred past a certain distance from the cortex, and there was no significant difference in anchor depth or integrity of the rotator cuff tendon based on shoulder BMD. Therefore, minimal settling in the all-suture anchor did not show clinical significance.
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Affiliation(s)
- Kyunghan Ro
- Shoulder and Elbow Clinic, Bonbridge Hospital, Seoul, Republic of Korea
| | - Sung-Min Rhee
- Shoulder and Elbow Clinic, Department of Orthopaedic Surgery, College of Medicine, Kyung Hee University, Seoul, Republic of Korea
| | - Jung Youn Kim
- Department of Orthopaedic Surgery, Kangnam Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Republic of Korea
| | - Myung Seo Kim
- Department of Orthopaedic Surgery, Ulsan University Hospital, College of Medicine, University of Ulsan, Ulsan, Republic of Korea
| | - Jong Dae Kim
- Shoulder and Elbow Clinic, Department of Orthopaedic Surgery, College of Medicine, Kyung Hee University, Seoul, Republic of Korea
| | - Hojin Lee
- Shoulder and Elbow Clinic, Department of Orthopaedic Surgery, College of Medicine, Kyung Hee University, Seoul, Republic of Korea
| | - Yong Girl Rhee
- Shoulder and Elbow Clinic, Department of Orthopaedic Surgery, College of Medicine, Kyung Hee University, Seoul, Republic of Korea
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da Mota Costa MR, de Abreu Oliveira AL, de Moura Vidal LW, Moran Ramos R, de Oliveira Campos I, Hansson K, Ley CJ, Olsson U, Borg NO, Höglund OV. Comparison of macroscopic resorption time for a self-locking device and suture material in ovarian pedicle ligation in dogs. Vet Rec 2019; 184:478. [PMID: 30872363 DOI: 10.1136/vr.104732] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 10/19/2018] [Accepted: 02/07/2019] [Indexed: 11/03/2022]
Abstract
A resorbable self-locking device (LigaTie) was developed to enable safe and easy surgical ligation of blood vessels. The aim of this study was to compare the long-term in vivo resorption of the device to a commercially available suture of equivalent material (Maxon) following ovarian pedicle ligation. After ovariohysterectomy follow-up ultrasound examinations were performed monthly on 21 dogs ligated with the device and 22 dogs ligated with the suture material until no hyperechoic remnants, acoustic shadowing or local tissue reactions were detected. In both groups, the ovarian pedicles gradually decreased in size. Ligation material was considered macroscopically resorbed when ultrasound showed no signs of the device or suture, ovarian pedicle or tissue reaction. Macroscopic resorption had occurred without signs of complications and was complete by four months for sutures and 5.5 months for the device. The results show that resorption time in vivo for the resorbable self-locking device is mildly longer than suture of the same material and that no complications of device resorption were detected, supporting that the resorbable self-locking device is safe for in vivo use.
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Affiliation(s)
| | | | | | - Renato Moran Ramos
- Department of Animal Clinical and Surgery, Universidade Estadual Norte Fluminense, Alberto, Brazil
| | | | - Kerstin Hansson
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Charles J Ley
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Ulf Olsson
- Department of Energy and Technology, Swedish University of Agricultural Sciences, Applied statistics and mathematics, Uppsala, Sweden
| | | | - Odd Viking Höglund
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden.,Resorbable Devices AB, Uppsala, Sweden
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12
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Zhang T, Jin G, Han X, Gao Y, Zeng Q, Hou B, Zhang D. Multiscale modelling for the heterogeneous strength of biodegradable polyesters. J Mech Behav Biomed Mater 2019; 90:337-349. [DOI: 10.1016/j.jmbbm.2018.10.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 08/28/2018] [Accepted: 10/09/2018] [Indexed: 11/16/2022]
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13
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Laycock B, Nikolić M, Colwell JM, Gauthier E, Halley P, Bottle S, George G. Lifetime prediction of biodegradable polymers. Prog Polym Sci 2017. [DOI: 10.1016/j.progpolymsci.2017.02.004] [Citation(s) in RCA: 301] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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14
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Ben-Shaba S, Domb AJ. Synthesis of Pendent Carbonate Ester Groups onto Aliphatic Polycarbonates. J BIOACT COMPAT POL 2016. [DOI: 10.1177/0883911506068563] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The reactions of mono- -bromo ethyl carbonate with carboxylic acids, amines, and alcohols were investigated as a model tool for the preparation of novel aliphatic polycarbonate esters. The formation of the corresponding carbonate ester, carbamate, and carbonate derivatives, showed that of the three types of groups chosen to react with -bromo ethyl carbonate, only the carboxylate anions displaced the bromo group to form the corresponding -carbonate ester bond (R—COO—CH(CH3)—O—CO—CH2—CH3). This approach was applied to the synthesis of pendent carbonate ester groups onto aliphatic polycarbonates. The synthetic pathway involved partial bromination of polytrimethylene carbonate (PTMC) to Br-PTMC, which was then reacted with benzoic acid or acetic acid to form the corresponding benzoate and acetate pendent polycarbonate, respectively. The hydrolysis of Br-PTMC and its derivatives as possible biodegradable polymers were investigated. The benzoate group was more susceptible to hydrolysis than the carbonate group hence degradation of the ester catalyzed the hydrolysis of the polymer and improved its biodegradability. The decrease in molecular weight, the release profile for benzoic acid from the grafted polymer and the degradation of Br-PTMC, ACPTMC and PTMC, in terms of the change in pH, were evaluated.
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Affiliation(s)
- Shimon Ben-Shaba
- Department of Pharmacology and School of Pharmacy, Faculty of Health Sciences, Ben Gurion University of the Negev, P.O. Box 653, 84105, Beer Sheva, Israel,
| | - Abraham J. Domb
- Department of Medicinal Chemistry and Natural Products, School of Pharmacy, Faculty of Medicine, Hebrew University of Jerusalem, 91120 Jerusalem, Israel
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15
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Olewnik-Kruszkowska E, Kasperska P, Koter I. Effect of poly(ε-caprolactone) as plasticizer on the properties of composites based on polylactide during hydrolytic degradation. REACT FUNCT POLYM 2016. [DOI: 10.1016/j.reactfunctpolym.2016.03.026] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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16
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Xiong Y, Yu Z, Lang Y, Hu J, Li H, Yan Y, Tu C, Yang T, Song Y, Duan H, Pei F. In vitro stress effect on degradation and drug release behaviors of basic fibroblast growth factor--poly(lactic-co-glycolic-acid) microsphere. Drug Des Devel Ther 2016; 10:431-40. [PMID: 26869764 PMCID: PMC4734730 DOI: 10.2147/dddt.s93554] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
OBJECTIVE To study the degradation and basic fibroblast growth factor (bFGF) release activity of bFGF - poly(lactic-co-glycolic-acid) microsphere (bFGF-PLGA MS) under stress in vitro, including the static pressure and shearing force-simulating mechanical environment of the joint cavity. METHOD First, bFGF-PLGA MSs were created. Meanwhile, two self-made experimental instruments (static pressure and shearing force loading instruments) were initially explored to provide stress-simulating mechanical environment of the joint cavity. Then, bFGF-PLGA MSs were loaded into the two instruments respectively, to study microsphere degradation and drug release experiments. In the static pressure loading experiment, normal atmospheric pressure loading (approximately 0.1 MPa), 0.35 MPa, and 4.0 MPa pressure loading and shaking flask oscillation groups were designed to study bFGF-PLGA MS degradation and bFGF release. In the shearing force loading experiment, a pulsating pump was used to give the experimental group an output of 1,000 mL/min and the control group an output of 10 mL/min to carry out bFGF-PLGA MS degradation and drug release experiments. Changes of bFGF-PLGA MSs, including microsphere morphology, quality, weight-average molecular weight of polymer, and microsphere degradation and bFGF release, were analyzed respectively. RESULTS In the static pressure loading experiment, bFGF-PLGA MSs at different pressure were stable initially. The trend of molecular weight change, quality loss, and bFGF release was consistent. Meanwhile, microsphere degradation and bFGF release rates in the 4.0 MPa pressure loading group were faster than those in the normal and 0.35 MPa pressure loading groups. It was the fastest in the shaking flask group, showing a statistically significant difference (P<0.0001). In the shearing force loading experiment, there were no distinctive differences in the rates of microsphere degradation and bFGF release between experimental and control group. Meanwhile, microsphere degradation and bFGF release rates by shaking flask oscillation were obviously faster than those by shearing force only (P<0.0001). CONCLUSION There are significant effects on bFGF-PLGA MS degradation and bFGF release due to the interaction between extraction stress and time. Static pressure has a conspicuous influence on bFGF-PLGA MS degradation and release, especially at a pressure of 4.0 MPa. The shearing force has a slight effect on bFGF-PLGA MS degradation and drug release. On the contrary, shaking flask oscillation has a significantly distinctive effect.
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Affiliation(s)
- Yan Xiong
- Department of Orthopedics, West China Hospital, Sichuan University, Chengdu, Sichuan, People’s Republic of China
| | - Zeping Yu
- Department of Orthopedics, West China Hospital, Sichuan University, Chengdu, Sichuan, People’s Republic of China
| | - Yun Lang
- Department of Orthopedics, West China Hospital, Sichuan University, Chengdu, Sichuan, People’s Republic of China
| | - Juanyu Hu
- Department of Orthopedics, West China Hospital, Sichuan University, Chengdu, Sichuan, People’s Republic of China
| | - Hong Li
- Laboratory of Biomechanical Engineering, Sichuan University, Chengdu, Sichuan, People’s Republic of China
| | - Yonggang Yan
- Laboratory of Biomechanical Engineering, Sichuan University, Chengdu, Sichuan, People’s Republic of China
| | - Chongqi Tu
- Department of Orthopedics, West China Hospital, Sichuan University, Chengdu, Sichuan, People’s Republic of China
| | - Tianfu Yang
- Department of Orthopedics, West China Hospital, Sichuan University, Chengdu, Sichuan, People’s Republic of China
| | - Yueming Song
- Department of Orthopedics, West China Hospital, Sichuan University, Chengdu, Sichuan, People’s Republic of China
| | - Hong Duan
- Department of Orthopedics, West China Hospital, Sichuan University, Chengdu, Sichuan, People’s Republic of China
| | - Fuxing Pei
- Department of Orthopedics, West China Hospital, Sichuan University, Chengdu, Sichuan, People’s Republic of China
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Influence of pH on Morphology and Structure during Hydrolytic Degradation of the Segmented GL-b-[GL-co-TMC-co-CL]-b-GL Copolymer. FIBERS 2015. [DOI: 10.3390/fib3030348] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Limbert G, Omar R, Krynauw H, Bezuidenhout D, Franz T. The anisotropic mechanical behaviour of electro-spun biodegradable polymer scaffolds: Experimental characterisation and constitutive formulation. J Mech Behav Biomed Mater 2015; 53:21-39. [PMID: 26301317 DOI: 10.1016/j.jmbbm.2015.07.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 07/07/2015] [Accepted: 07/16/2015] [Indexed: 01/17/2023]
Abstract
Electro-spun biodegradable polymer fibrous structures exhibit anisotropic mechanical properties dependent on the degree of fibre alignment. Degradation and mechanical anisotropy need to be captured in a constitutive formulation when computational modelling is used in the development and design optimisation of such scaffolds. Biodegradable polyester-urethane scaffolds were electro-spun and underwent uniaxial tensile testing in and transverse to the direction of predominant fibre alignment before and after in vitro degradation of up to 28 days. A microstructurally-based transversely isotropic hyperelastic continuum constitutive formulation was developed and its parameters were identified from the experimental stress-strain data of the scaffolds at various stages of degradation. During scaffold degradation, maximum stress and strain in circumferential direction decreased from 1.02 ± 0.23 MPa to 0.38 ± 0.004 MPa and from 46 ± 11 % to 12 ± 2 %, respectively. In longitudinal direction, maximum stress and strain decreased from 0.071 ± 0.016 MPa to 0.010 ± 0.007 MPa and from 69 ± 24 % to 8 ± 2 %, respectively. The constitutive parameters were identified for both directions of the non-degraded and degraded scaffold for strain range varying between 0% and 16% with coefficients of determination r(2)>0.871. The six-parameter constitutive formulation proved versatile enough to capture the varying non-linear transversely isotropic behaviour of the fibrous scaffold throughout various stages of degradation.
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Affiliation(s)
- Georges Limbert
- National Centre for Advanced Tribology at Southampton (nCATS), Engineering Sciences, Faculty of Engineering and the Environment, University of Southampton, Southampton SO17 1BJ, UK; Bioengineering Science Research Group, Engineering Sciences, Faculty of Engineering and the Environment, University of Southampton, Southampton SO17 1BJ, UK; Division of Biomedical Engineering, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Observatory 7935, South Africa.
| | - Rodaina Omar
- Cardiovascular Research Unit, Chris Barnard Department of Cardiothoracic Surgery, Faculty of Health Sciences, University of Cape Town, Observatory 7935, South Africa
| | - Hugo Krynauw
- Cardiovascular Research Unit, Chris Barnard Department of Cardiothoracic Surgery, Faculty of Health Sciences, University of Cape Town, Observatory 7935, South Africa
| | - Deon Bezuidenhout
- Cardiovascular Research Unit, Chris Barnard Department of Cardiothoracic Surgery, Faculty of Health Sciences, University of Cape Town, Observatory 7935, South Africa
| | - Thomas Franz
- Division of Biomedical Engineering, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Observatory 7935, South Africa; Centre for Research in Computational and Applied Mechanics, University of Cape Town, Rondebosch 7701, South Africa; Research Office, University of Cape Town, Mowbray 7701, South Africa
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Ge S, Wang Y, Tian J, Lei D, Yu Q, Wang G. Anin vitrostudy on the biocompatibility of WE magnesium alloys. J Biomed Mater Res B Appl Biomater 2015; 104:482-7. [DOI: 10.1002/jbm.b.33388] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 12/13/2014] [Accepted: 01/22/2015] [Indexed: 02/01/2023]
Affiliation(s)
- Shuping Ge
- College of Chemistry and Chemical Engineering; Chongqing University of Technology; Chongqing 400054 China
| | - Yi Wang
- Key Laboratory of Biorheological Science and Technology; Chongqing University, Ministry of Education, Bioengineering College of Chongqing University; Chongqing 400044 China
| | - Jie Tian
- Key Laboratory of Biorheological Science and Technology; Chongqing University, Ministry of Education, Bioengineering College of Chongqing University; Chongqing 400044 China
| | - Daoxi Lei
- Key Laboratory of Biorheological Science and Technology; Chongqing University, Ministry of Education, Bioengineering College of Chongqing University; Chongqing 400044 China
| | - Qingsong Yu
- Center for Surface Science and Plasma Technology; Department of Mechanical and Aerospace Engineering; University of Missouri; Columbia Missouri 65211
| | - Guixue Wang
- Key Laboratory of Biorheological Science and Technology; Chongqing University, Ministry of Education, Bioengineering College of Chongqing University; Chongqing 400044 China
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Höglund OV, Ingman J, Södersten F, Hansson K, Borg N, Lagerstedt AS. Ligation of the spermatic cord in dogs with a self-locking device of a resorbable polyglycolic based co-polymer--feasibility and long-term follow-up study. BMC Res Notes 2014; 7:825. [PMID: 25410023 PMCID: PMC4247741 DOI: 10.1186/1756-0500-7-825] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 11/05/2014] [Indexed: 11/15/2022] Open
Abstract
Background New surgical techniques are developed to enable a quicker, easier and safer surgery with reduced risk of complications and shortened time needed for recovery. A resorbable device, a self-locking loop, was designed for surgical ligation. The objective of this pilot study was to investigate the feasibility of ligating the spermatic cord with the device, its biocompatibility and long-term resorption in dogs. Results The device was made of a block co-polymer (glycolide and trimethylene carbonate), manufactured by injection moulding and consisted of a flexible band running through a case with a locking mechanism. Ten devices were tested for ligation of the spermatic cords in five dogs admitted for routine neutering. The dogs were monitored by physical examination and ultrasonography of the site of ligation, area of spermatic cord and medial iliac lymph nodes regularly until no hyperechoic remnants of the device or acoustic shadowing or local tissue reactions were observed. Haemostasis of the spermatic cords was achieved with the devices. On ultrasonography the devices were seen as hyperechoic structures for 2 months after neutering causing acoustic shadowing for 1 month. The dogs were monitored for 3 – 5 months after surgery. Gradual decrease in echogenicity and final disappearance of the hyperechoic structures suggested resorption. Macroscopic and histological post mortem examinations were performed in one dog at 3 months after surgery. Post mortem examination showed a tissue reaction of a suture granuloma that was restricted in extent at site of the device. Conclusions The results of this pilot study suggest biocompatibility and indicate that ligation of the spermatic cord is feasible with the device.
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Affiliation(s)
- Odd V Höglund
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Box 7054, SE-750 07 Uppsala, Sweden.
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Mitchell MK, Hirt DE. Degradation of PLA fibers at elevated temperature and humidity. POLYM ENG SCI 2014. [DOI: 10.1002/pen.24003] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Mary K. Mitchell
- Department of Chemical and Biomolecular Engineering; Clemson University; Clemson South Carolina 29634
| | - Douglas E. Hirt
- Department of Chemical and Biomolecular Engineering; Clemson University; Clemson South Carolina 29634
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22
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Márquez Y, Franco L, Turon P, Rodríguez-Galán A, Puiggalí J. Study on the hydrolytic degradation of the segmented GL-b-[GL-co-TMC-co-CL]-b-GL copolymer with application as monofilar surgical suture. Polym Degrad Stab 2013. [DOI: 10.1016/j.polymdegradstab.2013.10.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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23
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Vieira AC, Guedes RM, Tita V. Considerations for the design of polymeric biodegradable products. JOURNAL OF POLYMER ENGINEERING 2013. [DOI: 10.1515/polyeng-2012-0150] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Several biodegradable polymers are used in many products with short life cycles. The performance of a product is mostly conditioned by the materials selection and dimensioning. Strength, maximum strain and toughness will decrease along its degradation, and it should be enough for the predicted use. Biodegradable plastics can present short-term performances similar to conventional plastics. However, the mechanical behavior of biodegradable materials, along the degradation time, is still an unexplored subject. The maximum strength failure criteria, as a function of degradation time, have traditionally been modeled according to first order kinetics. In this work, hyperelastic constitutive models are discussed. An example of these is shown for a blend composed of poly(L-lactide) acid (PLLA) and polycaprolactone (PCL). A numerical approach using ABAQUS is presented, which can be extended to other 3D geometries. Thus, the material properties of the model proposed are automatically updated in correspondence to the degradation time, by means of a user material subroutine. The parameterization was achieved by fitting the theoretical curves with the experimental data of tensile tests made on a PLLA-PCL blend (90:10) for different degradation times. The results obtained by numerical simulations are compared to experimental data, showing a good correlation between both results.
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Mohammad AK, Reineke JJ. Quantitative Detection of PLGA Nanoparticle Degradation in Tissues following Intravenous Administration. Mol Pharm 2013; 10:2183-9. [DOI: 10.1021/mp300559v] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Abdul Khader Mohammad
- Department of Pharmaceutical
Sciences, Eugene Applebaum
College of Pharmacy and Health Sciences, Wayne State University, Detroit,
Michigan 48201, United States
| | - Joshua J. Reineke
- Department of Pharmaceutical
Sciences, Eugene Applebaum
College of Pharmacy and Health Sciences, Wayne State University, Detroit,
Michigan 48201, United States
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Wähnert D, Stolarczyk Y, Hoffmeier KL, Raschke MJ, Hofmann GO, Mückley T. Long-term stability of angle-stable versus conventional locked intramedullary nails in distal tibia fractures. BMC Musculoskelet Disord 2013; 14:66. [PMID: 23425016 PMCID: PMC3598499 DOI: 10.1186/1471-2474-14-66] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Accepted: 02/19/2013] [Indexed: 11/10/2022] Open
Abstract
Background In the last years intramedullary nailing has become the treatment of choice for most displaced diaphyseal tibia fractures. In contrast intramedullary nailing of distal tibia fractures is accompanied by problems like decreased biomechanical stability. Nevertheless the indications for intramedullary nailing have been extended to include even more distal fractures. The purpose of this study was to compare long-term mechanical characteristics of angle-stable versus conventional locked intramedullary nails in the treatment of unstable distal tibia fractures. Therefore, the effect of time on the mechanical properties of biodegradable sleeves was assessed. Methods 8 pairs of fresh, frozen porcine tibiae were used. The expert tibial nail (Synthes) was equipped with either three conventional locking screws (CL) or the angle-stable locking system (AS), consisting of a special ASLS screw and a biodegradable sleeve. Biomechanical testing included torsional and axial loading at different time-points over 12 weeks. Results The AS group showed a significantly higher torsional stiffness at all time-points (at least 60%) compared to the CL group (p < 0.001). The neutral zone was at least 5 times higher in the CL group (p < 0.001). The mean axial stiffness was maximum 10% higher (week 6) in the angle-stable locked group compared to the conventional group. There was no significant change of the torsional mechanical characteristics over the 12 weeks in both groups (p > 0.05). For axial stiffness and range of motion significant differences were found in the AS group. Conclusions The angle-stable locking system (ASLS) with the biodegradable sleeve provides significantly higher long-term stability. Especially the differences determined under torsional loading in this study may have clinical relevance. The ASLS permits the potential to decrease complications like secondary loss of reduction and mal-/non-union.
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Affiliation(s)
- Dirk Wähnert
- Department of Trauma-, Hand- and Reconstructive Surgery, Friedrich Schiller University Jena, Erlanger Allee 101, Jena 07747, Germany.
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Study on the hydrolytic degradation of glycolide/trimethylene carbonate copolymers having different microstructure and composition. Polym Degrad Stab 2013. [DOI: 10.1016/j.polymdegradstab.2012.10.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Stein T, Mehling AP, Ulmer M, Reck C, Efe T, Hoffmann R, Jäger A, Welsch F. MRI graduation of osseous reaction and drill hole consolidation after arthroscopic Bankart repair with PLLA anchors and the clinical relevance. Knee Surg Sports Traumatol Arthrosc 2012; 20:2163-73. [PMID: 22045195 DOI: 10.1007/s00167-011-1721-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Accepted: 10/10/2011] [Indexed: 12/20/2022]
Abstract
PURPOSE Conventionally, radiography studies revealed prolonged glenoidal drill hole visibilities with an unclear influence to the clinical outcome after arthroscopic Bankart repair using Poly-Laevo-Lactic-Acid (PLLA) anchors. The primary aim of the present study was the separated assessment of drill hole consolidation (DHC) and the concomitant osseous reaction (OR) of the glenoidal bio-degradation process in new specific magnetic resonance grading systems. In accordance with the specific DHC and the OR graduation, the clinical relevance was the secondary focus. METHODS Twenty-eight patients with arthroscopic Bankart repair using knotless PLLA anchors were prospectively followed and analyzed using a clinical scoring system (3, 6, 15 and 32 months). The T2-weighted OR and T1-weighted DHC were assessed using specific magnetic resonance imaging grading protocols (15 and 32 months). RESULTS Longitudinal assessments revealed successive clinical status improvements over time (32 months: Rowe 95.7 ± 3.8; Walch-Duplay 93.8 ± 6.6; Constant 93.9 ± 4.5; ASES 93.8 ± 6.9; DASH 28.6 ± 7.2; NAS(pain) 1.1 ± 1.3; NAS(function) 1.3 ± 1.4). The initial OR level regressed over the 15-32 month period while the DHC showed significant drill hole reductions (P < 0.05). The inferior glenoid revealed a significantly increased bio-degradation capacity (P < 0.05) with drill hole enlargements in 14.3%. Neither the OR nor the drill hole enlargements influenced the clinical status. In no case were clinical or radiologic signs for a foreign body reaction. CONCLUSION Knotless bio-anchors provide secure glenoidal fixation for Bankart repair without any specific clinical or MR evidence of an inflammatory response. The clinical status remained unaffected by the bio-degradation process. LEVEL OF EVIDENCE IV.
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Affiliation(s)
- T Stein
- Department of Sporttraumatology-Knee- and Shoulder-Surgery, Berufsgenossenschaftliche Unfallklinik Frankfurt am Main, Friedberger Landstraße 430, 60389, Frankfurt am Main, Germany.
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Tang CY, Wang ZW, Tsui CP, Bai YF, Gao B, Wu H. Damage modeling of degradable polymers under bulk erosion. J Appl Polym Sci 2012. [DOI: 10.1002/app.38404] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Lu DD, Yang LQ, Shi XL, Chang Y, Zhang H, Lei ZQ. Synthesis and Characterization of Amphiphilic Biodegradable Hyperbranched-linear-hyperbranched Copolymers Based on PEG, PLA, and BHP. INT J POLYM MATER PO 2012. [DOI: 10.1080/00914037.2011.610069] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Fajardo AD, Amador-Ortiz C, Chun J, Stewart D, Fleshman JW. Evaluation of Bioabsorbable Seamguard for Staple Line Reinforcement in Stapled Rectal Anastomoses. Surg Innov 2011; 19:288-94. [DOI: 10.1177/1553350611429025] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Introduction. The concept of staple line reinforcement is a growing area of interest. This study evaluated the feasibility and effect of using bioabsorbable Seamguard (BSG) to bolster end-to-end stapled rectal anastomoses in a porcine model. Methods. Eleven female 45-kg Yucatan domestic pigs were used. Each animal served as its own control by creating a BSG and nonreinforced anastomosis using a 29-mm end-to-end anastomotic stapling device. Reinforced anastomoses were randomized to proximal and distal positions along the rectum. Each staple line reinforcement agent consisted of adding BSG to the stapling device according to the manufacturer’s instructions. Barium enemas were then performed and the 2 anastomotic sites harvested. Each anastomosis underwent burst testing. The internal diameter of each anastomosis was measured and underwent pathologic review. Results. Bolstered anastomoses offered no strength advantage as burst pressures were no different as compared with unbolstered anastomoses. There was also no difference in anastomotic internal or external diameters. Only 1 stapled anastomosis burst during testing and none in the bolstered group. On histological analysis, there was a significant increase in inflammatory infiltrate in the bolstered group as compared with the stapled group ( P = .041), with a higher incidence of lymphocytes ( P = .047) and giant cells ( P = .037). There was no difference in mucosal loss at the anastomotic site, neovascularization, fibroblast presence, extent of fibrosis, muscle layer disruption, percentage of anastomosis replaced by collagen, and elastin deposition. Conclusions. The routine use of BSG bolsters in stapled rectal anastomoses is safe and results in equivalent anastomotic strength as traditional stapled anastomoses.
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Affiliation(s)
| | | | - Jonathan Chun
- Washington University in St Louis, Saint Louis, MO, USA
| | - David Stewart
- Penn State Milton S. Hershey Medical Center, Hershey, PA, USA
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Ng AHC, Ng NSP, Zhu GH, Lim LHY, Venkatraman SS. A fully degradable tracheal stent: In vitro and in vivo characterization of material degradation. J Biomed Mater Res B Appl Biomater 2011; 100:693-9. [DOI: 10.1002/jbm.b.32501] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Revised: 09/07/2011] [Accepted: 09/27/2011] [Indexed: 11/06/2022]
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Ma R, Chow R, Choi L, Diduch D. Arthroscopic rotator cuff repair: suture anchor properties, modes of failure and technical considerations. Expert Rev Med Devices 2011; 8:377-87. [PMID: 21542709 DOI: 10.1586/erd.11.4] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Rotator cuff injury and tears are a common source of shoulder pain, particularly among the elderly. Arthroscopic repair has now become the mainstay in the treatment of significant injuries that have failed conservative therapy. Compared with the traditional open technique, arthroscopic repair offers patients smaller incisions and less soft-tissue trauma, which result in improved postoperative pain and rehabilitation. The advances that have made arthroscopic repairs a reality includes improvement in arthroscopic rotator cuff instrumentation, particularly suture anchors. Suture anchors are used to reattach the torn rotator cuff tissue back onto the bone. Current rotator cuff anchors vary by design, anchor composition and suture materials. A treating physician should be aware of the advantages and limitations of these implants, which may influence the choice of one anchor over another. In addition to anchor variables, other factors that may affect the success of the repair include the local environment and surgical technique. In this article, various aspects of anchor design will be discussed. In addition, a concise review of technical considerations will also be discussed.
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Affiliation(s)
- Richard Ma
- Department of Orthopedic Surgery, University of Virginia Health System, PO Box 800159, Charlottesville, VA 22908, USA.
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Through-thickness control of polymer bioresorption via electron beam irradiation. Acta Biomater 2011; 7:548-57. [PMID: 20849986 DOI: 10.1016/j.actbio.2010.09.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2010] [Revised: 08/04/2010] [Accepted: 09/08/2010] [Indexed: 11/20/2022]
Abstract
Predicable and controlled degradation is not only central to the accurate delivery of bioactive agents and drugs, it also plays a vital role in key aspects of bone tissue engineering. The work addressed in this paper investigates the utilisation of e-beam irradiation in order to achieve a controlled (surface) degradation profile. This study focuses on the modification of commercially and clinically relevant materials, namely poly(L-lactic acid) (PLLA), poly(L-lactide-hydroxyapatite) (PLLA-HA), poly(L-lactide-glycolide) co-polymer (PLG) and poly(L-lactide-DL-lactide) co-polymer (PLDL). Samples were subjected to irradiation treatments using a 0.5MeV electron beam with delivered surface doses of 150 and 500 kGy. In addition, an acrylic attenuation shield was used for selected samples to control the penetration of the e-beam. E-beam irradiation induced chain scission in all polymers, as characterized by reduced molecular weights and glass transition temperatures (T(g)). Irradiation not only produced changes in the physical properties of the polymers but also had associated effects on surface erosion of the materials during hydrolytic degradation. Moreover, the extent to which both mechanical and hydrolytic degradation was observed is synonymous with the estimated penetration of the beam (as controlled by the employment of an attenuation shield).
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Pillai CKS, Sharma CP. Review Paper: Absorbable Polymeric Surgical Sutures: Chemistry, Production, Properties, Biodegradability, and Performance. J Biomater Appl 2010; 25:291-366. [DOI: 10.1177/0885328210384890] [Citation(s) in RCA: 209] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Among biomaterials used as implants in human body, sutures constitute the largest groups of materials having a huge market exceeding $1.3 billion annually. Sutures are the most widely used materials in wound closure and have been in use for many centuries. With the development of the synthetic absorbable polymer, poly(glycolic acid) (PGA) in the early 1970s, a new chapter has opened on absorbable polymeric sutures that got unprecedented commercial successes. Although several comparative evaluations of suture materials have been published, there were no serious attempts of late on a comprehensive review of production, properties, biodegradability, and performance of suture materials. This review proposes to bring to focus scattered data on chemistry, properties, biodegradability, and performance of absorbable polymeric sutures.
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Affiliation(s)
- Chennakkattu Krishna Sadasivan Pillai
- Division of Biosurface Technology, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences & Technology, Poojappura, Thiruvananthapuram 695 012, India
| | - Chandra P. Sharma
- Division of Biosurface Technology, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences & Technology, Poojappura, Thiruvananthapuram 695 012, India,
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A biomechanical comparison of a biodegradable volar locked plate with two titanium volar locked plates in a distal radius fracture model. ACTA ACUST UNITED AC 2010; 68:984-91. [PMID: 20016391 DOI: 10.1097/ta.0b013e3181b28962] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Volar plating is commonly used in the management of distal radius fractures; bioresorbable plates have attractive features. We compared a bioresorbable plate with a latest generation and an established locked titanium plate. METHODS Twenty-four fresh-frozen radii (12 pairs) were assigned to three mean bone mineral density-matched groups of eight radii each. A standardized extraarticular distal radius fracture was created and plated using one implant type per group. Postplating stiffness and displacement were studied in a first axial-loading test (15 cycles at 250 N). Next, biodegradation was simulated by 4 weeks' immersion in phosphate-buffered saline, followed by a second axial test. Finally, the specimens underwent cyclic loading (2,400 cycles at 250 N). RESULTS It is clear from the initial test that the LCP plate was significantly stiffer and displaced less than the bioresorbable plate. The outcome of the postimmersion tests is that one bioresorbable plate failed early on after 4 weeks' immersion, and the remaining bioresorbable plates and the T plates did not differ significantly. Cyclic tests conclude that the LCP plate was significantly superior to the other systems. One T plate and four of the bioresorbable plates failed, but none of the LCP plates failed. In the bioresorbable constructs, stability, time to failure, and bone mineral density were significantly correlated. CONCLUSIONS The LCP plate was biomechanically superior and may be generally recommended for the volar plating of distal radius fractures. Except one plate failure, the bioresorbable plate was similar to the T plate in the quasi-static tests and should, therefore, be considered for clinical studies, with patient selection confined, initially, only to candidates with good bone stock quality.
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Abstract
Colorectal anastomotic leak remains one of the most feared post-operative complications, particularly after anterior resection of the rectum with, the shift from abdomino-peritoneal resections to total mesorectal excision and primary anastomosis. The literature fails to demonstrate superiority of stapled over hand-sewn techniques in colorectal anastomosis, regardless of the level of anastomosis, although a high stricture rate was noted in the former technique. Thus, improvements in safety aspects of anastomosis and alternatives to hand-sewn and stapled techniques are being sought. Here, we review alternative anastomotic techniques used to fashion bowel anastomosis. Compression anastomosis using compression anastomotic clips, endoluminal compression anastomotic rings, AKA-2, biofragmental anastomotic rings, or Magnamosis all involve the concept of creating a sutureless end-to-end anastomosis by compressing two bowel ends together, leading to a simultaneous necrosis and healing process that joins the two lumens. Staple line reinforcement is a new approach that reduce the drawbacks of staplers used in colorectal practice, i.e. leakage, bleeding, misfiring, and inadequate tissue approximation. Various non-absorbable, semi or fully absorbable materials are now available. Two other techniques can provide alternative anastomotic support to the suture line: a colorectal drain and a polyester stent, which can be utilized in ultra-low rectal excision and can negate the formation of a defunctioning stoma. Doxycycline coated sutures have been used to overcome the post-operative weakness in anastomosis secondary to rapid matrix degradation mediated by matrix metalloproteinase. Another novel technique, the electric welding system, showed promising results in construction of a safe, neat, smooth sutureless bowel anastomosis. Various anastomotic techniques have been shown to be comparable to the standard techniques of suturing and stapling. However, most of these alternatives need to be accepted and optimized for future use.
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Qi YP, Miao ZM, Cheng SX, Zhang XZ. Fabrication and drug release properties of poly(5-benzyloxy-trimethylene-co-glycolide) microspheres. J Appl Polym Sci 2010. [DOI: 10.1002/app.30839] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Araújo MA, Cunha AM, Mota M. Changes on surface morphology of corn starch blend films. J Biomed Mater Res A 2010; 94:720-9. [DOI: 10.1002/jbm.a.32725] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Abstract
Aliphatic polyesters, such as polylactic acid (PLA), polyglycolic acid (PGA), polycaprolactone (PCL), polydioxone (PDO) and others, have been commonly used in biodegradable products. Hydrolytic and/or enzymatic chain cleavage of these materials leads to α-hydroxyacids, which, in most cases, are ultimately assimilated in human body or in a composting environment. However, each of these has some shortcomings, in terms of mechanical properties and degradation time, which restrict its applications. The combination of these materials, by copolymerization or blending, enables a range of mechanical properties and degradation rates. These are extremely promising approaches which can improve or tune the original properties of the polymers. A composite solution of several materials with different degradation rates also enables tuning the rate of degradation of a device and the mechanical properties. After immersion of an aliphatic polyester device, diffusion occurs very rapidly compared to hydrolysis. Therefore, it is usually considered that hydrolysis of ester bonds starts homogeneously and has traditionally been modelled according to a first order kinetics. In this experimental study, fibres of PLA-PCL, PGA-PCL, PDO and PGA, with two different dimensions, were characterized in terms of their degradation rate under three different environments (water, NaCl and PBS) at constant temperature (37°C). Weights and mechanical properties were measured after six different degradation stages. Stages durations were different depending on materials, according to the predicted degradation times. As other thermoplastics, they are viscoelastic materials. In this experimental study mechanical properties of fibres were compared at different strain rates.
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Vieira A, Guedes R, Marques A. Development of ligament tissue biodegradable devices: A review. J Biomech 2009; 42:2421-30. [DOI: 10.1016/j.jbiomech.2009.07.019] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2008] [Revised: 07/02/2009] [Accepted: 07/05/2009] [Indexed: 10/20/2022]
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Nho SJ, Provencher MT, Seroyer ST, Romeo AA. Bioabsorbable anchors in glenohumeral shoulder surgery. Arthroscopy 2009; 25:788-93. [PMID: 19560644 DOI: 10.1016/j.arthro.2008.08.018] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2008] [Revised: 08/26/2008] [Accepted: 08/27/2008] [Indexed: 02/02/2023]
Abstract
The use of implants to provide glenohumeral soft tissue fixation has changed dramatically over the past few decades, from point tack fixation to metallic suture anchors to bioabsorbable suture anchors. Bioabsorbable suture anchors have largely replaced metallic anchors because of concerns of implant loosening, migration, and chondral injury. Although the safety and efficacy of bioabsorbable anchors has been well documented, there are numerous reports regarding the early failure related to implant bioabsorbable implant breakage or premature degradation. Patients with anchor-related complications generally present with pain and/or stiffness, and the surgeon should have a high index of suspicion if a patient does not progress as expected. Glenohumeral synovitis, glenoid osteolysis, loose bodies, and chondral injury are some of the notable complications that have been reported. Careful attention to proper anchor insertion techniques can limit the potential for complications. Newer materials, such as polyetheretherketone and other composites, have recently been introduced. These materials may address concerns of biocompatibility and material strength, but additional rigorous in vitro and in vivo trials need to be conducted before their use becomes widespread.
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Affiliation(s)
- Shane J Nho
- Division of Sports Medicine, Department of Orthopedic Surgery, Rush University Medical Center, Rush Medical College of Rush University, Chicago, Illinois 60612, USA.
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Leonard DJ, Pick LT, Farrar DF, Dickson GR, Orr JF, Buchanan FJ. The modification of PLA and PLGA using electron-beam radiation. J Biomed Mater Res A 2009; 89:567-74. [PMID: 18435410 DOI: 10.1002/jbm.a.31998] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The degradable polymers polylactide (PLA) and polylactide-co-glycolide (PLGA) have found widespread use in modern medical practice. However, their slow degradation rates and tendency to lose strength before mass have caused problems. The aim of this study was to ascertain whether treatment with e-beam radiation could address these problems. Samples of PLA and PLGA were manufactured and placed in layered stacks, 8.1 mm deep, before exposure to 50 kGy of e-beam radiation from a 1.5 MeV accelerator. Gel permeation chromatography testing showed that the molecular weight of both materials was depth-dependent following irradiation, with samples nearest to the treated surface showing a reduced molecular weight. Samples deeper than 5.4 mm were unaffected. Computer modeling of the transmission of a 1.5 MeV e-beam in these materials corresponded well with these findings. An accelerated mass-loss study of the treated materials found that the samples nearest the irradiated surface initiated mass loss earlier, and at later stages showed an increased percentage mass loss. It was concluded that e-beam radiation could modify the degradation of bioabsorbable polymers to potentially improve their performance in medical devices, specifically for improved orthopedic fixation.
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Klos K, Sauer S, Hoffmeier K, Gras F, Fröber R, Hofmann GO, Mückley T. Biomechanical evaluation of plate osteosynthesis of distal fibula fractures with biodegradable devices. Foot Ankle Int 2009; 30:243-51. [PMID: 19321102 DOI: 10.3113/fai.2009.0243] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND This study compared fixation with a titanium one-third tubular plate and one lag-screw vs. fixation with biodegradable plates with one lag-screw applied with two different plate-screw patterns. MATERIALS AND METHODS Ten pairs of fibulas were osteotomied, plated (titanium plate with one lag screw vs. absorbable 2/8 plate-screws crossing vs. 0/8 plate-screws crossing the osteotomy gap). and tested in torsion and bending to obtain stiffness and neutral-zone (NZ) data. Tests were performed using 5 load cycles. No load to failure was performed. Biodegradation was simulated by 6 week immersion in phosphate-buffered saline after which the testing protocol was repeated. The specimens were then loaded with 100 N in bending. RESULTS Post-implantation, there were no significant differences, in torsion and bending, regarding the NZ or the stiffness, between the 2/8 biodegradable plate and the titanium plate. The 0/8 pattern performed significantly less well in terms of stiffness and NZ in the initial torsion test, and significantly less well in terms of stiffness in the initial bending test. After 6 weeks' immersion, all biodegradable constructs showed a significantly larger NZ and significantly reduced bending and torsional stiffness. When loaded with 100 N, four of the six 0/8 osteosyntheses failed. There were no significant differences between the 2/8 pattern and the titanium plates. CONCLUSION In a model of a Weber-B fracture, the use of a 2/8 biodegradable plate construct initially did not differ statistically to that obtained with a one-third tubular titanium plate. After immersion the 2/8 construct withstood some physiological load. CLINICAL RELEVANCE For the fixation of ankle fractures with a biodegradable plate of the type employed in this study, the use of fracture-gap-crossing screws is recommended.
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Ricalde P, Caccamese J, Norby C, Posnick JC, Hartman MJ, von Fraunhofer JA. Strength Analysis of 6 Resorbable Implant Systems: Does Heating Affect the Stress-Strain Curve? J Oral Maxillofac Surg 2008; 66:2493-7. [DOI: 10.1016/j.joms.2008.06.096] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2008] [Accepted: 06/27/2008] [Indexed: 11/25/2022]
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A comparison of gastrojejunal anastomoses with or without buttressing in a porcine model. Surg Endosc 2008; 23:800-7. [PMID: 18830746 DOI: 10.1007/s00464-008-0079-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2008] [Revised: 06/16/2008] [Accepted: 06/23/2008] [Indexed: 11/27/2022]
Abstract
INTRODUCTION The addition of staple-line reinforcements on circular anastomoses has not been well studied. We histologically and mechanically analyzed circular- stapled anastomoses with and without bioabsorbable staple-line reinforcement (SeamGuard, W. L. Gore & Associates, Flagstaff, AZ) in a porcine model. METHODS Gastrojejunal anastomoses were constructed using a #25 EEA Proximate ILS (Ethicon Endo-Surgery, Cincinnati, OH) mechanical stapling device with and without Bioabsorbable SeamGuard (BSG). Gastrojejunal anastomoses were resected acutely and at 1 week, and burst-pressure testing and histological analysis were performed. Standardized grading systems for inflammation, collagen deposition, vascularity, and serosal inflammation were used to compare the two anastomosis types. RESULTS Acute burst pressures were significantly higher with BSG than with staples alone (1.37 versus 0.39 psi, p=0.0075). Burst pressures at 1 week were significantly lower with BSG than with staples alone (2.24 versus 3.86 psi, p=0.0353); however, both readings were above normal physiologic intestinal pressures. There was no statistical difference in inflammation (13.4 versus 15.6, p=0.073), width of mucosa (3.2 mm versus 3.2 mm, p=0.974), adhesion formation (0 versus 0.5, p=0.575), number of blood vessels (0.5 versus 1.0, p=0.056), or serosal inflammation (2.0 versus 1.0, p=0.27) between the stapled anastomoses and those buttressed with BSG. Stapled-only anastomoses had statistically more collagen (2.0 versus 1.0, p=0.005) than the anastomoses supported with BSG. CONCLUSIONS The addition of BSG as a staple-line reinforcement acutely improves the burst strength of a circular anastomosis but not at 1 week. At 1 week, a decrease in collagen content with the BSG-buttressed stapled anastomosis was the only difference in the histologic parameters studied with no difference in vascularity, adhesions, or inflammation. The long-term effect of BSG on anastomotic strength or scarring is yet to be determined. The clinical implications may include decreased stricture formation and also decreased strength at anastomoses.
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Deng M, Chen G, Burkley D, Zhou J, Jamiolkowski D, Xu Y, Vetrecin R. A study on in vitro degradation behavior of a poly(glycolide-co-L-lactide) monofilament. Acta Biomater 2008; 4:1382-91. [PMID: 18442954 DOI: 10.1016/j.actbio.2008.03.011] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2007] [Revised: 02/07/2008] [Accepted: 03/20/2008] [Indexed: 11/29/2022]
Abstract
The in vitro degradation behaviors of a poly(glycolide-co-l-lactide) 90/10 monofilament were investigated in phosphate buffer solution at pH 7.4 over a temperature range of 27.5-47.5 degrees C. The property changes of the monofilament with time at different temperatures were evaluated by tensile mechanical test, gel permeation chromatography analysis, and image techniques (optical microscopy, scanning electron microscopy and atomic force microscopy). The interrelationships among material properties, in vitro time and experimental conditions were explored. The results showed that the polymer monofilament gradually lost its tensile strength and molecular weight with increasing in vitro time. The hydrolytic degradation of the monofilaments followed a first order behavior. Higher temperatures accelerated the degradation process significantly. It was found that for a given tensile breaking strength retention (BSR), the dependence of degradation time on temperature could be illustrated by an Arrhenius-type equation, from which the activation energy was derived. Further analysis indicated that there are well-defined relationships between molecular weight and tensile strength, which could be illustrated mathematically. Finally, the microscopic evaluation of the monofilament samples revealed visible changes in morphology on the surface and cross-section area during degradation process. The results from atomic force microscopy showed that the surface roughness of the monofilament tended to increase with the in vitro time.
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Affiliation(s)
- Meng Deng
- R&D Division, ETHICON, Inc., Johnson & Johnson Company, P.O. Box 151, Somerville, NJ 08876, USA.
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Lyu S, Schley J, Loy B, Lind D, Hobot C, Sparer R, Untereker D. Kinetics and time-temperature equivalence of polymer degradation. Biomacromolecules 2007; 8:2301-10. [PMID: 17579477 DOI: 10.1021/bm070313n] [Citation(s) in RCA: 139] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We studied the hydrolysis kinetics of amorphous polylactide. It was found the hydrolysis rate had a slow-to-fast transition at a certain molecular weight (Mn). This transition was not correlated with the mass loss and water uptake of samples, nor the pH values of testing media. We speculated that this transition was due to the slow diffusion of polymer chain ends. The chain ends did not significantly promote the hydrolysis of samples until their concentrations (approximately 1/Mn) reached a critical value. The degradation tests were also conducted over a temperature range from 37 to 90 degrees C. A time-temperature equivalent relationship of degradation processes was established and a master curve spanning a time range equivalent to 3-5 years at 37 degrees C was constructed. This master curve can be used to predict polymer degradation processes based on accelerated tests. The functional time and disappearance time of degradable polymers were also discussed.
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Affiliation(s)
- Suping Lyu
- Medtronic Corporate Science and Technology, Minneapolis, MN 55432, USA.
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Im JN, Kim JK, Kim HK, In CH, Lee KY, Park WH. In vitro and in vivo degradation behaviors of synthetic absorbable bicomponent monofilament suture prepared with poly(p-dioxanone) and its copolymer. Polym Degrad Stab 2007. [DOI: 10.1016/j.polymdegradstab.2006.12.011] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Abstract
The use of biodegradable materials as implants has revolutionized the way medicine is practiced today. This review provides a general description of salient biodegradable polymeric materials currently used in arthroscopy. These materials include polyglycolic acid, self-reinforced polyglycolic acid, poly-L-lactic acid, self-reinforced polylactic-L-acid, poly-D-L-lactic acid, copolymer of poly-D-L-lactic acid polyglycolic acid, and polyglyconate. The mechanical strength, degradation properties, and widespread use of these materials, especially in the knee and shoulder, are discussed individually. Also discussed are the relatively few complications that are related to these materials' arthroscopic use. Future directions in biodegradable materials, including smart polymers, are also considered. In the future, novel techniques to identify the ideal polymer for a particular application will need to be developed to minimize the risk for implant complications.
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Affiliation(s)
- Najmuddin J Gunja
- Department of Bioengineering, Rice University, Houston, TX 77005, USA
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