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Siess M, Steinke H, Zwirner J, Hammer N. On a potential morpho-mechanical link between the gluteus maximus muscle and pelvic floor tissues. Sci Rep 2023; 13:22901. [PMID: 38129498 PMCID: PMC10739724 DOI: 10.1038/s41598-023-50058-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 12/14/2023] [Indexed: 12/23/2023] Open
Abstract
Stress urinary incontinence presents a condition not only found in female elderlies, but also in young athletes participating in high-impact sports such as volleyball or trampolining. Repeated jumps appear to be a predisposing factor. Yet the pathophysiology remains incompletely elucidated to date; especially with regard to the influence of the surrounding buttock tissues including gluteus maximus. The present study assessed the morpho-mechanical link between gluteus maximus and the pelvic floor female bodies. 25 pelves obtained from Thiel embalmed females were studied in a supine position. Strands of tissues connecting gluteus maximus with the pelvic floor obtained from 20 sides were assessed mechanically. Plastinates were evaluated to verify the dissection findings. In total, 49 hemipelves were included for data acquisition. The fascia of gluteus maximus yielded connections to the subcutaneous tissues, the fascia of the external anal sphincter and that of obturator internus and to the fascia of the urogenital diaphragm. The connection between gluteus maximus and the urogenital diaphragm withstood an average force of 23.6 ± 17.3 N. Cramér φ analyses demonstrated that the connections of the fasciae connecting gluteus maximus with its surroundings were consistent in the horizontal and sagittal planes, respectively. In conclusion, gluteus maximus is morphologically densely linked to the pelvic floor via strands of connective tissues investing the adjacent muscles. Though gluteus maximus has also been reported to facilitate urinary continence, the here presented morpho-mechanical link suggests that it may also have the potential to contribute to urinary stress incontinence. Future research combining clinical imaging with in-situ testing may help substantiate the potential influence from a clinical perspective.
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Affiliation(s)
- Maximilian Siess
- Division of Macroscopic and Clinical Anatomy, Gottfried Schatz Research Center, Medical University of Graz, Auenbruggerplatz 25, 8036, Graz, Austria
| | - Hanno Steinke
- Institute of Anatomy, University of Leipzig, Leipzig, Germany
| | - Johann Zwirner
- Institute of Legal Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Niels Hammer
- Division of Macroscopic and Clinical Anatomy, Gottfried Schatz Research Center, Medical University of Graz, Auenbruggerplatz 25, 8036, Graz, Austria.
- Department of Orthopedic and Trauma Surgery, University of Leipzig, Leipzig, Germany.
- Medical Branch, Fraunhofer Institute for Machine Tools and Forming Technology (IWU), Chemnitz, Germany.
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2
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Burk J, Wittenberg-Voges L, Schubert S, Horstmeier C, Brehm W, Geburek F. Treatment of Naturally Occurring Tendon Disease with Allogeneic Multipotent Mesenchymal Stromal Cells: A Randomized, Controlled, Triple-Blinded Pilot Study in Horses. Cells 2023; 12:2513. [PMID: 37947591 PMCID: PMC10650642 DOI: 10.3390/cells12212513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Revised: 10/13/2023] [Accepted: 10/19/2023] [Indexed: 11/12/2023] Open
Abstract
The treatment of tendinopathies with multipotent mesenchymal stromal cells (MSCs) is a promising option in equine and human medicine. However, conclusive clinical evidence is lacking. The purpose of this study was to gain insight into clinical treatment efficacy and to identify suitable outcome measures for larger clinical studies. Fifteen horses with early naturally occurring tendon disease were assigned to intralesional treatment with allogeneic adipose-derived MSCs suspended in serum or with serum alone through block randomization (dosage adapted to lesion size). Clinicians and horse owners remained blinded to the treatment during 12 months (seven horses per group) and 18 months (seven MSC-group and five control-group horses) of follow-up including clinical examinations and diagnostic imaging. Clinical inflammation, lameness, and ultrasonography scores improved more over time in the MSC group. The lameness score difference significantly improved in the MSC group compared with the control group after 6 months. In the MSC group, five out of the seven horses were free of re-injuries and back to training until 12 and 18 months. In the control group, three out of the seven horses were free of re-injuries until 12 months. These results suggest that MSCs are effective for the treatment of early-phase tendon disease and provide a basis for a larger controlled study.
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Affiliation(s)
- Janina Burk
- Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210 Vienna, Austria
| | - Liza Wittenberg-Voges
- Clinic for Horses, University of Veterinary Medicine Hannover, Foundation, Bünteweg 9, 30559 Hannover, Germany;
| | - Susanna Schubert
- Institute of Human Genetics, University of Leipzig Medical Center, Philipp-Rosenthal-Strasse 55, 04103 Leipzig, Germany;
| | - Carolin Horstmeier
- Department for Horses, Veterinary Teaching Hospital, University of Leipzig, An den Tierkliniken 21, 04103 Leipzig, Germany; (C.H.); (W.B.)
| | - Walter Brehm
- Department for Horses, Veterinary Teaching Hospital, University of Leipzig, An den Tierkliniken 21, 04103 Leipzig, Germany; (C.H.); (W.B.)
| | - Florian Geburek
- Clinic for Horses, University of Veterinary Medicine Hannover, Foundation, Bünteweg 9, 30559 Hannover, Germany;
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Hammer N, Ondruschka B, Berghold A, Kuenzer T, Pregartner G, Scholze M, Schulze-Tanzil GG, Zwirner J. Sample size considerations in soft tissue biomechanics. Acta Biomater 2023; 169:168-178. [PMID: 37517620 DOI: 10.1016/j.actbio.2023.07.036] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 07/12/2023] [Accepted: 07/23/2023] [Indexed: 08/01/2023]
Abstract
Biomechanical experiments help link tissue morphology with load-deformation characteristics. A tissue-dependent minimum sample number is indispensable to obtain accurate material properties. Stress-strain properties were retrieved from human dura mater and scalp skin, exemplifying two distinct soft tissues. Minimum sample sizes necessary for a stable estimation of material properties were obtained in a simulation study. One-thousand random samples were sequentially drawn for calculating the point at which a majority of the estimators settled within a corridor of stability at given tolerance levels around a 'complete' reference for the mean, median and coefficient of variation. Stable estimations of means and medians can be achieved below sample sizes of 30 at a ± 20%-tolerance within 80%-conformity for scalp skin and dura. Lower tolerance levels or higher conformity dramatically increase the required sample size. Conformity was barely ever reached for the coefficient of variation. The parameter type appears decisive for achieving conformity. STATEMENT OF SIGNIFICANCE: Biomechanical trials utilizing human tissues are needed to obtain material properties for surgical repair, tissue engineering and modeling purposes. Linking tissue mechanics with morphology helps elucidate form-function relationships, the 'morpho-mechanical link'. For material properties to be accurate, it is vital to examine a minimum number of samples. This number may vary between tissues, and the effects of intrinsic tissue characteristics on data accuracy are unclear to date. This study used data obtained from human dura and skin to compute minimum sample sizes required for estimating material properties at a stable level. It was shown that stable estimations are possible at a ± 20%-tolerance within 80%-conformity below sample sizes of 30. Higher accuracy warrants much higher sample sizes for most material properties.
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Affiliation(s)
- Niels Hammer
- Division of Macroscopic and Clinical Anatomy, Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria; Department of Orthopedic and Trauma Surgery, University of Leipzig, Leipzig, Germany; Division of Biomechatronics, Fraunhofer Institute for Machine Tools and Forming Technology Dresden, Germany.
| | - Benjamin Ondruschka
- Institute of Legal Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Andrea Berghold
- Institute for Medical Informatics, Statistics and Documentation, Medical University of Graz, Graz, Austria
| | - Thomas Kuenzer
- Institute for Medical Informatics, Statistics and Documentation, Medical University of Graz, Graz, Austria
| | - Gudrun Pregartner
- Institute for Medical Informatics, Statistics and Documentation, Medical University of Graz, Graz, Austria
| | - Mario Scholze
- Institute of Materials Science and Engineering, Chemnitz University of Technology, Chemnitz, Germany
| | | | - Johann Zwirner
- Institute of Legal Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; Department of Oral Sciences, University of Otago, Dunedin, New Zealand
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4
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Fatigue Testing of Human Flexor Tendons Using a Customized 3D-Printed Clamping System. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12157836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Improved surgical procedures and implant developments for ligament or tendon repair require an in-depth understanding of tissue load-deformation and fatigue properties. Cyclic testing will provide crucial information on the behavior of these materials under reoccurring loads and on fatigue strength. Sparse data are available describing soft tissue behavior under cyclic loading. To examine fatigue strength, a new technology was trialed deploying 3D-printing to facilitate and standardize cyclic tests aiming to determine tendon fatigue behavior. Cadaveric flexor digitorum tendons were harvested and mounted for tensile testing with no tapering being made, using 3D-printed clamps and holder arms, while ensuring a consistent testing length. Loads ranging between 200 to 510 N were applied at a frequency of 4 Hz, and cycles to failure ranged between 8 and >260,000. S–N curves (Woehler curves) were generated based on the peak stresses and cycles to failure. Power regression yielded a combined coefficient of determination of stress and cycles to failure of R2 = 0.65, while the individual coefficients for tissues of single donors ranged between R2 = 0.54 and R2 = 0.88. The here-presented results demonstrate that S–N curves of human tendons can be obtained using a standardized setting deploying 3D-printing technology.
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Steel S, Pearcy Q, Li K, Scholze M, Zwirner J. The relationship between the pH value of a hydration solution and the biomechanical properties of Crosado-embalmed human iliotibial bands. J Mech Behav Biomed Mater 2022; 132:105266. [DOI: 10.1016/j.jmbbm.2022.105266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 04/27/2022] [Accepted: 05/03/2022] [Indexed: 11/16/2022]
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Zwirner J, Ondruschka B, Scholze M, Schulze-Tanzil G, Hammer N. Biomechanical characterization of human temporal muscle fascia in uniaxial tensile tests for graft purposes in duraplasty. Sci Rep 2021; 11:2127. [PMID: 33483525 PMCID: PMC7822884 DOI: 10.1038/s41598-020-80448-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Accepted: 12/16/2020] [Indexed: 01/03/2023] Open
Abstract
The human temporal muscle fascia (TMF) is used frequently as a graft material for duraplasty. Encompassing biomechanical analyses of TMF are lacking, impeding a well-grounded biomechanical comparison of the TMF to other graft materials used for duraplasty, including the dura mater itself. In this study, we investigated the biomechanical properties of 74 human TMF samples in comparison to an age-matched group of dura mater samples. The TMF showed an elastic modulus of 36 ± 19 MPa, an ultimate tensile strength of 3.6 ± 1.7 MPa, a maximum force of 16 ± 8 N, a maximum strain of 13 ± 4% and a strain at failure of 17 ± 6%. Post-mortem interval correlated weakly with elastic modulus (r = 0.255, p = 0.048) and the strain at failure (r = − 0.306, p = 0.022) for TMF. The age of the donors did not reveal significant correlations to the TMF mechanical parameters. Compared to the dura mater, the here investigated TMF showed a significantly lower elastic modulus and ultimate tensile strength, but a larger strain at failure. The human TMF with a post-mortem interval of up to 146 h may be considered a mechanically suitable graft material for duraplasty when stored at a temperature of 4 °C.
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Affiliation(s)
- Johann Zwirner
- Department of Anatomy, University of Otago, Dunedin, New Zealand. .,Institute of Legal Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
| | - Benjamin Ondruschka
- Institute of Legal Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Institute of Legal Medicine, University of Leipzig, Leipzig, Germany
| | - Mario Scholze
- Institute of Materials Science and Engineering, Chemnitz University of Technology, Chemnitz, Germany.,Department of Macroscopic and Clinical Anatomy, Medical University of Graz, Graz, Austria
| | - Gundula Schulze-Tanzil
- Institute of Anatomy and Cell Biology, Paracelsus Medical University, Salzburg and Nuremberg, Germany
| | - Niels Hammer
- Department of Macroscopic and Clinical Anatomy, Medical University of Graz, Graz, Austria. .,Department of Orthopaedic and Trauma Surgery, University of Leipzig, Leipzig, Germany. .,Fraunhofer IWU, Dresden, Germany.
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7
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Zwirner J, Ondruschka B, Scholze M, Hammer N. Surface coating and speckling of the human iliotibial tract does not affect its load-deformation properties. Sci Rep 2020; 10:20747. [PMID: 33247150 PMCID: PMC7695729 DOI: 10.1038/s41598-020-77299-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 10/29/2020] [Indexed: 01/23/2023] Open
Abstract
Stochastic surface patterns form an important requirement to facilitate digital image correlation and to subsequently quantify material properties of various tissues when loaded and deformed without artefacts arising from material slippage. Depending on the samples' natural colour, a surface pattern is created by speckling with colour or dye only, or it requires combined surface coating and speckling before to enhance the contrast, to facilitate high-quality data recording for mechanical evaluation. However, it is unclear to date if the colours deployed for coating and speckling do significantly alter the biomechanical properties of soft tissues. The given study investigated the biomechanical properties of 168 human iliotibial tract samples as a model for collagen-rich soft tissues, separated into four groups: untreated, graphite speckling only, water-based coating plus graphite speckling and solvent-based coating plus graphite speckling following a standardized approach of application and data acquisition. The results reveal that elastic modulus, ultimate tensile strength and strain at maximum force of all groups were similar and statistically non-different (p ≥ 0.69). Qualitatively, the speckle patterns revealed increasing contrast differences in the following order: untreated, graphite speckling only, water-based coating plus graphite speckling and solvent-based coating plus graphite speckling. Conclusively, both coating by water- and solvent-based paints, as well as exclusive graphite speckling, did not significantly influence the load-deformation parameters of the here used human iliotibial tract as a model for collagen-rich soft tissues. In consequence, water- and solvent-based coating paints seem equally suitable to coat collagen-rich soft tissues for digital image correlation, resulting in suitable speckle patterns and unbiased data acquisition.
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Affiliation(s)
- Johann Zwirner
- Department of Anatomy, University of Otago, Dunedin, New Zealand.
| | - Benjamin Ondruschka
- Institute of Legal Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Institute of Legal Medicine, University of Leipzig, Leipzig, Germany
| | - Mario Scholze
- Institute of Materials Science and Engineering, Chemnitz University of Technology, Chemnitz, Germany
- Department of Macroscopic and Clinical Anatomy, Medical University of Graz, Graz, Austria
| | - Niels Hammer
- Department of Macroscopic and Clinical Anatomy, Medical University of Graz, Graz, Austria.
- Department of Orthopaedic and Trauma Surgery, University of Leipzig, Leipzig, Germany.
- Fraunhofer IWU, Dresden, Germany.
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8
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Load-deformation characteristics of acellular human scalp: assessing tissue grafts from a material testing perspective. Sci Rep 2020; 10:19243. [PMID: 33159106 PMCID: PMC7648071 DOI: 10.1038/s41598-020-75875-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Accepted: 10/05/2020] [Indexed: 11/13/2022] Open
Abstract
Acellular matrices seem promising scaffold materials for soft tissue regeneration. Biomechanical properties of such scaffolds were shown to be closely linked to tissue regeneration and cellular ingrowth. This given study investigated uniaxial load-deformation properties of 34 human acellular scalp samples and compared these to age-matched native tissues as well as acellular dura mater and acellular temporal muscle fascia. As previously observed for human acellular dura mater and temporal muscle fascia, elastic modulus (p = 0.13) and ultimate tensile strength (p = 0.80) of human scalp samples were unaffected by the cell removal. Acellular scalp samples showed a higher strain at maximum force compared to native counterparts (p = 0.02). The direct comparison of acellular scalp to acellular dura mater and temporal muscle fascia revealed a higher elasticity (p < 0.01) and strain at maximum force (p = 0.02), but similar ultimate tensile strength (p = 0.47). Elastic modulus and ultimate tensile strength of acellular scalp decreased with increasing post-mortem interval. The elongation behavior formed the main biomechanical difference between native and acellular human scalp samples with elastic modulus and ultimate tensile strength being similar when comparing the two.
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9
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Zwirner J, Scholze M, Ondruschka B, Hammer N. What is Considered a Variation of Biomechanical Parameters in Tensile Tests of Collagen-Rich Human Soft Tissues? - Critical Considerations Using the Human Cranial Dura Mater as a Representative Morpho-Mechanic Model. MEDICINA (KAUNAS, LITHUANIA) 2020; 56:E520. [PMID: 33027931 PMCID: PMC7600870 DOI: 10.3390/medicina56100520] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 09/27/2020] [Accepted: 09/28/2020] [Indexed: 12/23/2022]
Abstract
Background and Objectives: Profound knowledge on the load-dependent behavior of human soft tissues is required for the development of suitable replacements as well as for realistic computer simulations. Regarding the former, e.g., the anisotropy of a particular biological tissue has to be represented with site- and direction-dependent particular mechanical values. Contrary to this concept of consistent mechanical properties of a defined soft tissue, mechanical parameters of soft tissues scatter considerably when being determined in tensile tests. In spite of numerous measures taken to standardize the mechanical testing of soft tissues, several setup- and tissue-related factors remain to influence the mechanical parameters of human soft tissues to a yet unknown extent. It is to date unclear if measurement extremes should be considered a variation or whether these data have to be deemed incorrect measurement outliers. This given study aimed to determine mechanical parameters of the human cranial dura mater as a model for human soft tissues using a highly standardized protocol and based on this, critically evaluate the definition for the term mechanical "variation" of human soft tissue. Materials and Methods: A total of 124 human dura mater samples with an age range of 3 weeks to 94 years were uniformly retrieved, osmotically adapted and mechanically tested using customized 3D-printed equipment in a quasi-static tensile testing setup. Scanning electron microscopy of 14 samples was conducted to relate the mechanical parameters to morphological features of the dura mater. Results: The here obtained mechanical parameters were scattered (elastic modulus = 46.06 MPa, interquartile range = 33.78 MPa; ultimate tensile strength = 5.56 MPa, interquartile range = 4.09 MPa; strain at maximum force = 16.58%, interquartile range = 4.81%). Scanning electron microscopy revealed a multi-layered nature of the dura mater with varying fiber directions between its outer and inner surface. Conclusions: It is concluded that mechanical parameters of soft tissues such as human dura mater are highly variable even if a highly standardized testing setup is involved. The tissue structure and composition appeared to be the main contributor to the scatter of the mechanical parameters. In consequence, mechanical variation of soft tissues can be defined as the extremes of a biomechanical parameter due to an uncontrollable change in tissue structure and/or the respective testing setup.
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Affiliation(s)
- Johann Zwirner
- Department of Anatomy, University of Otago, Dunedin 9016, New Zealand
| | - Mario Scholze
- Institute of Materials Science and Engineering, Chemnitz University of Technology, 09125 Chemnitz, Germany;
- Department of Macroscopic and Clinical Anatomy, Medical University of Graz, 8010 Graz, Austria
| | - Benjamin Ondruschka
- Institute of Legal Medicine, University Medical Center Hamburg-Eppendorf, 22529 Hamburg, Germany;
| | - Niels Hammer
- Department of Macroscopic and Clinical Anatomy, Medical University of Graz, 8010 Graz, Austria
- Department of Orthopaedic and Trauma Surgery, University of Leipzig, 04103 Leipzig, Germany
- Fraunhofer IWU, 01187 Dresden, Germany
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10
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Scholze M, Safavi S, Li KC, Ondruschka B, Werner M, Zwirner J, Hammer N. Standardized tensile testing of soft tissue using a 3D printed clamping system. HARDWAREX 2020; 8:e00159. [PMID: 35498242 PMCID: PMC9041186 DOI: 10.1016/j.ohx.2020.e00159] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 11/03/2020] [Accepted: 11/16/2020] [Indexed: 06/14/2023]
Abstract
Biomechanical testing of soft tissues forms the backbone in the experimental validation of tissue engineering and for modelling purposes. The standardized testing of soft tissues requires different experimental protocols and fixtures compared to hard tissues or non-biological materials due to their characteristics. Some of the most commonly-used clamping methods for soft tissue testing affect the tissues' mechanical properties as chemicals are involved to decelerate degradation and autolysis. Moreover, they are unsuitable for standardized and high-throughput testing. Material slippage is also a recurrent unwanted influence on the testing routine with impact on measurement validity. Addressing these issues, this protocol presents a clamping system for simplified testing of biological soft tissues with all necessary components manufactured utilizing 3D printing technology. Templates allow trimming the samples into standardized shapes and sizes while preparation tables facilitate clamping in a fixed distance. The key parts of the system are clamps with a pyramid design, which allow the mounting of biological soft tissues before transferring it into the testing device and minimize material slippage during tensile testing. Flexible holder arms are used to transfer samples from preparation tables into the testing device and simplify positioning. Mechanical testing itself is performed with digital image correlation for precise strain measurements.
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Affiliation(s)
- Mario Scholze
- Institute of Materials Science and Engineering, Chemnitz University of Technology, Chemnitz, Germany
- Department of Clinical and Macroscopic Anatomy, Medical University of Graz, Graz, Austria
| | - Sarah Safavi
- Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - Kai Chun Li
- Department of Oral Rehabilitation, Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
| | - Benjamin Ondruschka
- Institute of Legal Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Michael Werner
- Fraunhofer Institute for Machine Tools and Forming Technology IWU, Dresden, Germany
- Institute of Anatomy, University of Leipzig, Leipzig, Germany
| | - Johann Zwirner
- Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - Niels Hammer
- Department of Clinical and Macroscopic Anatomy, Medical University of Graz, Graz, Austria
- Fraunhofer Institute for Machine Tools and Forming Technology IWU, Dresden, Germany
- Department of Orthopedic and Trauma Surgery, University of Leipzig, Leipzig, Germany
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11
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Zwirner J, Zhang M, Ondruschka B, Akita K, Hammer N. An ossifying bridge - on the structural continuity between the Achilles tendon and the plantar fascia. Sci Rep 2020; 10:14523. [PMID: 32884015 PMCID: PMC7471908 DOI: 10.1038/s41598-020-71316-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 08/13/2020] [Indexed: 12/18/2022] Open
Abstract
Highly regular aligned trabeculae are found in the superficial posterior and inferior calcaneus appearing to connect the Achilles tendon (AT) to the plantar fascia (PF) in a bridge-like manner. This provides a morphological basis for the stretching-based heel pain treatment. However, the continuity of collagen fibres between the AT and the PF remains debated controversially to date. The given study morphologically investigated the AT-calcaneus-PF complex using histology and plastination. Moreover, the AT-calcaneus-PF complex was biomechanically mapped based on 13 sub-regions with a total of 76 tested samples. Regular calcaneal trabeculae were surrounded by tendon-like collagen fibre bundles and adipocytes. The orientation of calcaneal trabeculae was further closely related to the course of the PF collagen fibre bundles. The pooled biomechanical analysis revealed low elastic moduli (minimum = 4 MPa) and ultimate tensile strengths of the decalcified calcaneal samples (minimum = 0.4 MPa) and the calcaneal periostea (minimum = 2 MPa) and high respective values (elastic modulus maximum of 144 MPa; ultimate tensile strength maximum of 29 MPa) for the PF samples compared to the other sub-regions. This study provides structural evidence for a morphological connection between the AT and PF via the highly aligned calcaneal trabeculae of the posterior calcaneus. The AT-calcaneus-PF complex was biomechanically mapped to allow for an assessment of its site-dependent mechanical characteristics.
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Affiliation(s)
- Johann Zwirner
- Department of Anatomy, University of Otago, Dunedin, New Zealand. .,Department of Clinical Anatomy, Tokyo Medical and Dental University, Tokyo, Japan.
| | - Ming Zhang
- Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - Benjamin Ondruschka
- Institute of Legal Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Keichi Akita
- Department of Clinical Anatomy, Tokyo Medical and Dental University, Tokyo, Japan
| | - Niels Hammer
- Department of Macroscopic and Clinical Anatomy, Medical University of Graz, Graz, Austria. .,Department of Orthopaedic and Trauma Surgery, University of Leipzig, Leipzig, Germany. .,Fraunhofer IWU, Dresden, Germany.
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12
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Zwirner J, Ondruschka B, Scholze M, Schulze-Tanzil G, Hammer N. Mechanical properties of native and acellular temporal muscle fascia for surgical reconstruction and computational modelling purposes. J Mech Behav Biomed Mater 2020; 108:103833. [DOI: 10.1016/j.jmbbm.2020.103833] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 04/20/2020] [Accepted: 04/24/2020] [Indexed: 01/12/2023]
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13
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Sednieva Y, Viste A, Naaim A, Bruyère-Garnier K, Gras LL. Strain Assessment of Deep Fascia of the Thigh During Leg Movement: An in situ Study. Front Bioeng Biotechnol 2020; 8:750. [PMID: 32850692 PMCID: PMC7403494 DOI: 10.3389/fbioe.2020.00750] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 06/11/2020] [Indexed: 11/30/2022] Open
Abstract
Fascia is a fibrous connective tissue present all over the body. At the lower limb level, the deep fascia that is overlying muscles of the outer thigh and sheathing them (fascia lata) is involved in various pathologies. However, the understanding and quantification of the mechanisms involved in these sheathing effects are still unclear. The aim of this study is to observe and quantify the strain field of the fascia lata, including the iliotibial tract (ITT), during a passive movement of the knee. Three fresh postmortem human subjects were studied. To measure hip and knee angles during knee flexion-extension, passive movements from 0° to around 120° were recorded with a motion analysis system and strain fields of the fascia were acquired using digital image correlation. Strains were computed for three areas of the fascia lata: anterior fascia, lateral fascia, and ITT. Mean principal strains showed different strain mechanisms depending on location on the fascia and knee angle. For the ITT, two strain mechanisms were observed depending on knee movement: compression is observed when the knee is extended relative to the reference position of 47°, however, tension and pure shear can be observed when the knee is flexed. For the anterior and lateral fascia, in most cases, minor strain is higher than major strain in absolute value, suggesting high tissue compression probably due to microstructural fiber rearrangements. This in situ study is the first attempt to quantify the superficial strain field of fascia lata during passive leg movement. The study presents some limitations but provides a step in understanding strain mechanism of the fascia lata during passive knee movement.
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Affiliation(s)
- Yuliia Sednieva
- Univ Lyon, Université Claude Bernard Lyon 1, Univ Gustave Eiffel, IFSTTAR, LBMC UMR_T9406, Lyon, France
| | - Anthony Viste
- Univ Lyon, Université Claude Bernard Lyon 1, Univ Gustave Eiffel, IFSTTAR, LBMC UMR_T9406, Lyon, France
- Hospices Civils de Lyon, Hôpital Lyon Sud, Chirurgie Orthopédique, Pierre-Bénite, France
| | - Alexandre Naaim
- Univ Lyon, Université Claude Bernard Lyon 1, Univ Gustave Eiffel, IFSTTAR, LBMC UMR_T9406, Lyon, France
| | - Karine Bruyère-Garnier
- Univ Lyon, Université Claude Bernard Lyon 1, Univ Gustave Eiffel, IFSTTAR, LBMC UMR_T9406, Lyon, France
| | - Laure-Lise Gras
- Univ Lyon, Université Claude Bernard Lyon 1, Univ Gustave Eiffel, IFSTTAR, LBMC UMR_T9406, Lyon, France
- *Correspondence: Laure-Lise Gras,
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Zwirner J, Ondruschka B, Scholze M, Hammer N. Passive load-deformation properties of human temporal muscle. J Biomech 2020; 106:109829. [DOI: 10.1016/j.jbiomech.2020.109829] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 04/21/2020] [Accepted: 05/05/2020] [Indexed: 10/24/2022]
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Zwirner J, Scholze M, Waddell JN, Ondruschka B, Hammer N. Mechanical Properties of Human Dura Mater in Tension - An Analysis at an Age Range of 2 to 94 Years. Sci Rep 2019; 9:16655. [PMID: 31723169 PMCID: PMC6853942 DOI: 10.1038/s41598-019-52836-9] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 10/22/2019] [Indexed: 01/11/2023] Open
Abstract
Realistic human head models are of great interest in traumatic brain injury research and in the forensic pathology courtroom and teaching. Due to a lack of biomechanical data, the human dura mater is underrepresented in head models. This study provides tensile data of 73 fresh human cranial dura mater samples retrieved from an area between the anterior middle and the posterior middle meningeal artery. Tissues were adapted to their native water content using the osmotic stress technique. Tensile tests were conducted under quasi-static uniaxial testing conditions with simultaneous digital image correlation. Human temporal dura mater is mechanically highly variable with regards to its elastic modulus of 70 ± 44 MPa, tensile strength of 7 ± 4 MPa, and maximum strain of 11 ± 3 percent. Mechanical properties of the dura mater did not vary significantly between side nor sex and decreased with the age of the cadaver. Both elastic modulus and tensile strength appear to have constant mechanical parameters within the first 139 hours post mortem. The mechanical properties provided by this study can help to improve computational and physical human head models. These properties under quasi-static conditions do not require adjustments for side nor sex, whereas adjustments of tensile properties accompanied with normal aging may be of interest.
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Affiliation(s)
- Johann Zwirner
- Department of Anatomy, University of Otago, Dunedin, New Zealand.
| | - Mario Scholze
- Institute of Materials Science and Engineering, Chemnitz University of Technology, Chemnitz, Germany
| | - John Neil Waddell
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
| | | | - Niels Hammer
- Department of Anatomy, University of Otago, Dunedin, New Zealand. .,Department of Orthopedic and Trauma Surgery, University of Leipzig, Leipzig, Germany. .,Fraunhofer IWU, Dresden, Germany. .,Department of Anatomy, Medical University of Graz, Graz, Austria.
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Mechanical and morphological description of human acellular dura mater as a scaffold for surgical reconstruction. J Mech Behav Biomed Mater 2019; 96:38-44. [DOI: 10.1016/j.jmbbm.2019.04.035] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 04/02/2019] [Accepted: 04/18/2019] [Indexed: 11/21/2022]
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Tensile properties of the human iliotibial tract depend on height and weight. Med Eng Phys 2019; 69:85-91. [DOI: 10.1016/j.medengphy.2019.05.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 04/02/2019] [Accepted: 05/13/2019] [Indexed: 01/14/2023]
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Zwirner J, Scholze M, Ondruschka B, Hammer N. Tissue biomechanics of the human head are altered by Thiel embalming, restricting its use for biomechanical validation. Clin Anat 2019; 32:903-913. [DOI: 10.1002/ca.23409] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 05/13/2019] [Accepted: 05/16/2019] [Indexed: 01/10/2023]
Affiliation(s)
- Johann Zwirner
- Department of Anatomy University of Otago Dunedin New Zealand
| | - Mario Scholze
- Institute of Materials Science and Engineering Chemnitz University of Technology Chemnitz Germany
| | | | - Niels Hammer
- Department of Anatomy University of Otago Dunedin New Zealand
- Department of Orthopedic and Trauma Surgery University of Leipzig Germany
- Fraunhofer IWU Dresden Germany
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Water-content related alterations in macro and micro scale tendon biomechanics. Sci Rep 2019; 9:7887. [PMID: 31133713 PMCID: PMC6536550 DOI: 10.1038/s41598-019-44306-z] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 05/14/2019] [Indexed: 11/17/2022] Open
Abstract
Though it is known that the water content of biological soft tissues alters mechanical properties, little attempt has been made to adjust the tissue water content prior to biomechanical testing as part of standardization procedures. The objective of this study was to examine the effects of altered water content on the macro and micro scale mechanical tissues properties. Human iliotibial band samples were obtained during autopsies to osmotically adapt their water content. Macro mechanical tensile testing of the samples was conducted with digital image correlation, and micro mechanical tests using atomic force microscopy. Analyses were conducted for elastic moduli, tensile strength, and strain at maximum force, and correlations for water content, anthropometric data, and post-mortem interval. Different mechanical properties exist at different water concentrations. Correlations to anthropometric data are more likely to be found at water concentrations close to the native state. These data underline the need for adapting the water content of soft tissues for macro and micro biomechanical experiments to optimize their validity. The osmotic stress protocol provides a feasible and reliable standardization approach to adjust for water content-related differences induced by age at death, post-mortem interval and tissue processing time with known impact on the stress-strain properties.
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An Investigation on the Correlation between the Mechanical Properties of Human Skull Bone, Its Geometry, Microarchitectural Properties, and Water Content. JOURNAL OF HEALTHCARE ENGINEERING 2019; 2019:6515797. [PMID: 31249655 PMCID: PMC6556309 DOI: 10.1155/2019/6515797] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 05/04/2019] [Indexed: 11/18/2022]
Abstract
With increasingly detailed imaging and mechanical analysis, modalities need arises to update methodology and assessment criteria for skull bone analysis to understand how bone microarchitecture and the presence of attached tissues may affect the response to mechanical load. The main aim was to analyze the effect of macroscopic and microstructural features, as well as periosteal attachment, on the mechanical properties of human skull bone. Fifty-six skull specimens from ethanol-phenoxyethanol-embalmed cadavers were prepared from two human cadavers. Assuming symmetry of the skull, all samples from one-half each were stripped of periosteum and dura mater, while the soft tissues were kept intact on the remaining samples on the contralateral side. The specimens were analyzed using microcomputed tomography to assess trabecular connectivity density, total surface area, and volume ratio. The specimens were loaded under three-point bend tests until fracture with optical co-registration. The bone fragments were then lyophilized to measure their water content. With increasingly detailed imaging and mechanical analysis modalities, there is a need to update methodology and assessment criteria for skull bone analysis to understand how the bone microarchitecture and the presence of attached tissues may affect the response to mechanical load. The mechanical properties were negatively correlated to bone thickness and water content. Conversely, most microarchitectural features did not influence either mechanical parameter. The correlation between mechanical response data and morphologic properties remains similar between the results of embalmed tissues presented here and fresh osseous tissue from literature data. The findings presented here add to the existing methodology to assess human skull for research purposes. The interaction between most microarchitectural features in ethanol-phenoxyethanol-embalmed embalmed skull samples and bending stress appear to be minute.
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Hochstrat E, Müller M, Frank A, Michel P, Hansen U, Raschke MJ, Kronenberg D, Stange R. Cryopreservation of tendon tissue using dimethyl sulfoxide combines conserved cell vitality with maintained biomechanical features. PLoS One 2019; 14:e0215595. [PMID: 31002728 PMCID: PMC6474606 DOI: 10.1371/journal.pone.0215595] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 04/04/2019] [Indexed: 01/31/2023] Open
Abstract
Biomechanical research on tendon tissue evaluating new treatment strategies to frequently occurring clinical problems regarding tendon degeneration or trauma is of expanding scientific interest. In this context, storing tendon tissue deep-frozen is common practice to collect tissue and analyze it under equal conditions. The commonly used freezing medium, phosphate buffered saline, is known to damage cells and extracellular matrix in frozen state. Dimethyl sulfoxide, however, which is used for deep-frozen storage of cells in cell culture preserves cell vitality and reduces damage to the extracellular matrix during freezing. In our study, Achilles tendons of 26 male C57/Bl6 mice were randomized in five groups. Tendons were deep frozen in dimethyl sulfoxide or saline undergoing one or four freeze-thaw-cycles and compared to an unfrozen control group analyzing biomechanical properties, cell viability and collagenous structure. In electron microscopy, collagen fibrils of tendons frozen in saline appeared more irregular in shape, while dimethyl sulfoxide preserved the collagenous structure during freezing. In addition, treatment with dimethyl sulfoxide preserved cell viability visualized with an MTT-Assay, while tendons frozen in saline showed no remaining metabolic activity, indicating total destruction of cells during freezing. The biomechanical results revealed no differences between tendons frozen once in saline or dimethyl sulfoxide. However, tendons frozen four times in saline showed a significantly higher Young’s modulus over all strain rates compared to unfrozen tendons. In conclusion, dimethyl sulfoxide preserves the vitality of tendon resident cells and protects the collagenous superstructure during the freezing process resulting in maintained biomechanical properties of the tendon.
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Affiliation(s)
- Eva Hochstrat
- Department of Regenerative Musculoskeletal Medicine, Institute for Musculoskeletal Medicine, University Hospital Münster, Westfälische Wilhelms-University, Münster, Germany
| | - Marcus Müller
- Department of Trauma-, Hand-, and Reconstructive Surgery, University Hospital Münster, Münster, Germany
| | - Andre Frank
- Department of Trauma-, Hand-, and Reconstructive Surgery, University Hospital Münster, Münster, Germany
| | - Philipp Michel
- Department of Regenerative Musculoskeletal Medicine, Institute for Musculoskeletal Medicine, University Hospital Münster, Westfälische Wilhelms-University, Münster, Germany
- Department of Trauma-, Hand-, and Reconstructive Surgery, University Hospital Münster, Münster, Germany
| | - Uwe Hansen
- Department of Molecular Medicine, Institute for Musculoskeletal Medicine, Westfälische Wilhelms-University, Münster, Germany
| | - Michael J. Raschke
- Department of Trauma-, Hand-, and Reconstructive Surgery, University Hospital Münster, Münster, Germany
| | - Daniel Kronenberg
- Department of Regenerative Musculoskeletal Medicine, Institute for Musculoskeletal Medicine, University Hospital Münster, Westfälische Wilhelms-University, Münster, Germany
| | - Richard Stange
- Department of Regenerative Musculoskeletal Medicine, Institute for Musculoskeletal Medicine, University Hospital Münster, Westfälische Wilhelms-University, Münster, Germany
- * E-mail:
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Scholze M, Singh A, Lozano PF, Ondruschka B, Ramezani M, Werner M, Hammer N. Utilization of 3D printing technology to facilitate and standardize soft tissue testing. Sci Rep 2018; 8:11340. [PMID: 30054509 PMCID: PMC6063914 DOI: 10.1038/s41598-018-29583-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 07/13/2018] [Indexed: 01/12/2023] Open
Abstract
Three-dimensional (3D) printing has become broadly available and can be utilized to customize clamping mechanisms in biomechanical experiments. This report will describe our experience using 3D printed clamps to mount soft tissues from different anatomical regions. The feasibility and potential limitations of the technology will be discussed. Tissues were sourced in a fresh condition, including human skin, ligaments and tendons. Standardized clamps and fixtures were 3D printed and used to mount specimens. In quasi-static tensile tests combined with digital image correlation and fatigue trials we characterized the applicability of the clamping technique. Scanning electron microscopy was utilized to evaluate the specimens to assess the integrity of the extracellular matrix following the mechanical tests. 3D printed clamps showed no signs of clamping-related failure during the quasi-static tests, and intact extracellular matrix was found in the clamping area, at the transition clamping area and the central area from where the strain data was obtained. In the fatigue tests, material slippage was low, allowing for cyclic tests beyond 105 cycles. Comparison to other clamping techniques yields that 3D printed clamps ease and expedite specimen handling, are highly adaptable to specimen geometries and ideal for high-standardization and high-throughput experiments in soft tissue biomechanics.
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Affiliation(s)
- Mario Scholze
- Department of Anatomy, University of Otago, New Zealand Department of Anatomy, Dunedin, New Zealand. .,Institute of Materials Science and Engineering, Chemnitz University of Technology, Chemnitz, Germany.
| | - Aqeeda Singh
- Department of Anatomy, University of Otago, New Zealand Department of Anatomy, Dunedin, New Zealand
| | - Pamela F Lozano
- Department of Anatomy, University of Otago, New Zealand Department of Anatomy, Dunedin, New Zealand
| | - Benjamin Ondruschka
- Institute of Legal Medicine, Medical Faculty University of Leipzig, Leipzig, Germany
| | - Maziar Ramezani
- Department of Mechanical Engineering, Auckland University of Technology, Auckland, New Zealand
| | - Michael Werner
- Department of Trauma, Orthopedic and Plastic Surgery, University Hospital of Leipzig, Leipzig, Germany
| | - Niels Hammer
- Department of Anatomy, University of Otago, New Zealand Department of Anatomy, Dunedin, New Zealand. .,Department of Trauma, Orthopedic and Plastic Surgery, University Hospital of Leipzig, Leipzig, Germany. .,Fraunhofer Institute for Machine Tools and Forming Technology, Dresden, Germany.
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Schleifenbaum S, Prietzel T, Hädrich C, Möbius R, Sichting F, Hammer N. Tensile properties of the hip joint ligaments are largely variable and age-dependent - An in-vitro analysis in an age range of 14-93 years. J Biomech 2016; 49:3437-3443. [PMID: 27667477 DOI: 10.1016/j.jbiomech.2016.09.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2016] [Revised: 09/02/2016] [Accepted: 09/07/2016] [Indexed: 01/12/2023]
Abstract
INTRODUCTION Hip joint stability is maintained by the surrounding ligaments, muscles, and the atmospheric pressure exerted via these structures. It is unclear whether the ligaments are capable of preventing dislocation solely due to their tensile properties, and to what extent they undergo age-related changes. This study aimed to obtain stress-strain data of the hip ligaments over a large age range. METHODS Stress-strain data of the iliofemoral (IL), ischiofemoral (IS) and pubofemoral ligament (PF) were obtained from cadavers ranging between 14 and 93 years using a highly standardized setting. Maximum strains were compared to the distances required for dislocation. RESULTS Elastic modulus was 24.4 (IL), 22.4 (IS) and 24.9N/mm2 (PF) respectively. Maximum strain was 84.5%, 86.1%, 72.4% and ultimate stress 10.0, 7.7 and 6.5N/mm2 for the IL, IS and PF respectively. None of these values varied significantly between ligaments or sides. The IS' elastic modulus was higher and maximum strain lower in males. Lower elastic moduli of the PF and higher maximum strains for the IS and PF were revealed in the ≥55 compared to the <55 population. Maximum strain exceeded the dislocation distance of the IS without external hip joint rotation in females, and of the IS and cranial IL under external rotation in both genders. DISCUSSION Tensile and failure load properties of the hip joint ligaments are largely variable. The IS and PF change age-dependently. Though the hip ligaments contribute to hip stability, the IS and cranial IL may not prevent dislocation due to their elasticity.
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Affiliation(s)
- Stefan Schleifenbaum
- Department of Anatomy, University of Otago, Dunedin, New Zealand; Department of Orthopedics, Trauma and Plastic Surgery, University of Leipzig, Leipzig, Germany
| | - Torsten Prietzel
- Department of Orthopedics, Trauma and Plastic Surgery, University of Leipzig, Leipzig, Germany; Department of Orthopedics and Trauma Surgery, HELIOS Clinic Blankenhain, Blankenhain, Germany
| | - Carsten Hädrich
- Institute of Forensic Medicine, University of Leipzig, Germany
| | - Robert Möbius
- Institute of Anatomy, University of Leipzig, Leipzig, Germany
| | - Freddy Sichting
- Institute of Sport Science, Department Human Locomotion, Chemnitz University of Technology, Chemnitz, Germany
| | - Niels Hammer
- Department of Anatomy, University of Otago, Dunedin, New Zealand.
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Schleifenbaum S, Schmidt M, Möbius R, Wolfskämpf T, Schröder C, Grunert R, Hammer N, Prietzel T. Load and failure behavior of human muscle samples in the context of proximal femur replacement. BMC Musculoskelet Disord 2016; 17:149. [PMID: 27048598 PMCID: PMC4822308 DOI: 10.1186/s12891-016-0998-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 03/25/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND To ensure adequate function after orthopedic tumor reconstruction, it is important to reattach the remaining soft tissue to the implant. This study aimed at obtaining mechanical properties of textile muscle-implant and muscle-bone connections in a preliminary test. METHODS Two groups of soft-tissue attachment were mechanically tested and compared: Native bone-muscle samples obtained from human femora and muscles attached to a prosthetic implant by means of Trevira® attachment tubes. Additionally, muscle samples were tested with muscle fibers aligned parallel and perpendicular to the tension load. A uniaxial load was exerted upon all samples. RESULTS Failure loads of 26.7 ± 8.8 N were observed for the native bone-muscle group and of 18.1 ± 9.9 N for the Trevira® group. Elongations of 94.8 ± 36.2 % were observed for the native bone-muscle group and 79.3 ± 51.8 % for the Trevira® group. The location of failure was mainly observed in the central area of the muscle fibers. Muscle fibers with parallel fiber orientation (47.6 ± 11.5 N) yielded higher tensile strength than those with perpendicular fiber orientation (14.8 ± 4.1 N). CONCLUSIONS Our experiments showed that higher forces were transmitted in the origin and insertion areas than in areas of flat soft tissue reconstruction using attachment tubes. The data indicate that the tested material allows reattaching muscles, but without reinforcing the insertion site. Therefore, attachment tubes with region-dependent and potentially anisotropic material behavior might be advantageous to optimize muscle-bone load transmission after surgery, which may allow lower complication rates and shorter physical recovery.
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Affiliation(s)
- Stefan Schleifenbaum
- Department of Orthopedic, Trauma and Plastic Surgery, University of Leipzig, Liebigstraße 20, D-04103, Leipzig, Germany
| | - Michael Schmidt
- Department of Orthopedic, Trauma and Plastic Surgery, University of Leipzig, Liebigstraße 20, D-04103, Leipzig, Germany
| | - Robert Möbius
- Institute of Anatomy, University of Leipzig, Liebigstraße 13, D-04103, Leipzig, Germany
| | - Thomas Wolfskämpf
- Institute of Anatomy, University of Leipzig, Liebigstraße 13, D-04103, Leipzig, Germany
| | - Christian Schröder
- Department of Orthopaedic Surgery, Physical Medicine and Rehabilitation, University Hospital of Munich (LMU), Campus Grosshadern, Marchioninistraße 15, D-81377, Munich, Germany
| | - Ronny Grunert
- Fraunhofer-Institut für Werkzeugmaschinen und Umformtechnik IWU, Medizintechnik, Nöthnitzer Str. 44, D-01187, Dresden, Germany
| | - Niels Hammer
- Department of Anatomy, University of Otago, Lindo Ferguson Building, 270 Great King St., Dunedin, 9016, New Zealand.
| | - Torsten Prietzel
- Department of Orthopedic, Trauma and Plastic Surgery, University of Leipzig, Liebigstraße 20, D-04103, Leipzig, Germany
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Acellularization-Induced Changes in Tensile Properties Are Organ Specific - An In-Vitro Mechanical and Structural Analysis of Porcine Soft Tissues. PLoS One 2016; 11:e0151223. [PMID: 26960134 PMCID: PMC4784745 DOI: 10.1371/journal.pone.0151223] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 02/23/2016] [Indexed: 12/18/2022] Open
Abstract
Introduction Though xenogeneic acellular scaffolds are frequently used for surgical reconstruction, knowledge of their mechanical properties is lacking. This study compared the mechanical, histological and ultrastructural properties of various native and acellular specimens. Materials and Methods Porcine esophagi, ureters and skin were tested mechanically in a native or acellular condition, focusing on the elastic modulus, ultimate tensile stress and maximum strain. The testing protocol for soft tissues was standardized, including the adaption of the tissue’s water content and partial plastination to minimize material slippage as well as templates for normed sample dimensions and precise cross-section measurements. The native and acellular tissues were compared at the microscopic and ultrastructural level with a focus on type I collagens. Results Increased elastic modulus and ultimate tensile stress values were quantified in acellular esophagi and ureters compared to the native condition. In contrast, these values were strongly decreased in the skin after acellularization. Acellularization-related decreases in maximum strain were found in all tissues. Type I collagens were well-preserved in these samples; however, clotting and a loss of cross-linking type I collagens was observed ultrastructurally. Elastins and fibronectins were preserved in the esophagi and ureters. A loss of the epidermal layer and decreased fibronectin content was present in the skin. Discussion Acellularization induces changes in the tensile properties of soft tissues. Some of these changes appear to be organ specific. Loss of cross-linking type I collagen may indicate increased mechanical strength due to decreasing transverse forces acting upon the scaffolds, whereas fibronectin loss may be related to decreased load-bearing capacity. Potentially, the alterations in tissue mechanics are linked to organ function and to the interplay of cells and the extracellular matrix, which is different in hollow organs when compared to skin.
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Hammer N, Huster D, Boldt A, Hädrich C, Koch H, Möbius R, Schulze-Tanzil G, Scheidt HA. A preliminary technical study on sodium dodecyl sulfate-induced changes of the nano-structural and macro-mechanical properties in human iliotibial tract specimens. J Mech Behav Biomed Mater 2016; 61:164-173. [PMID: 26866452 DOI: 10.1016/j.jmbbm.2016.01.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 01/12/2016] [Accepted: 01/20/2016] [Indexed: 01/14/2023]
Abstract
INTRODUCTION Acellular scaffolds are frequently used for the surgical repair of ligaments and tendons. Even though data on the macro-mechanical properties related to the acellularization process exist, corresponding data on the nano-structural properties are still lacking. Such data would help identify target proteins of the formed extracellular matrix that are chemically altered by the acellularization. In this study we examined the altered structure by comparing molecular properties of collagens from native and acellular iliotibial tract samples to the macroscopic stress-strain behavior of tract samples. MATERIAL AND METHODS Matched pairs of five human iliotibial tract samples were obtained from five donors (mean age 28.2±4.7 years). One of each pair was acellularized using 1vol% sodium dodecyl sulfate (SDS) for 7 days. (13)C magic angle spinning nuclear magnetic resonance spectroscopy ((13)C CP MAS NMR) was utilized to compare the collagen overall secondary structure and internal dynamics of collagen-typical amino acid proteins. The resulting data was compared to age-matched stress-strain data of tract samples obtained in an uniaxial tensile setup and histologically. RESULTS Typical and nearly identical collagen (13)C CP MAS NMR spectra were found in the tract samples before and after acellularization with SDS. The characteristic collagen backbone remained intact in the native and acellular samples. Collagen molecular composition was largely unaltered in both conditions. Furthermore, a similar dynamic behavior was found for the amino acids Hyp γ, Pro α/Hyp α, Ala α, Gly α and Ala β. These minute alterations in the collagens' molecular properties related to acellularization with SDS were in line with the similarly minute changes in the macro-mechanical tensile behavior, such as the elastic modulus and ultimate stress. Histology showed intact type I collagens, minute amounts of elastins before and after acellularization and evidence for acellularization-induced reductions of proteoglycans. DISCUSSION Nano-structural properties of collagens are minutely affected by SDS treatment for acellularization, indicated by the molecular composition and dynamics. The lacking acellularization-related changes in the molecular structure properties of collagens in iliotibial tract samples are in line with the small alterations in their macro-mechanical tensile behavior. Though the given setup approaches soft tissue mechanics from both scaling extremes of mechanical testing, further structural analyzes are needed in a larger sample size to substantiate these findings.
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Affiliation(s)
- Niels Hammer
- Department of Anatomy, University of Otago, 270 Great King Street, Dunedin 9054, New Zealand.
| | - Daniel Huster
- Institute of Medical Physics and Biophysics, University of Leipzig, Faculty of Medicine, Leipzig, Germany
| | - Andreas Boldt
- Institute of Clinical Immunology, University of Leipzig, Faculty of Medicine, Leipzig, Germany; Translational Centre for Regenerative Medicine, University of Leipzig, Faculty of Medicine, Leipzig, Germany
| | - Carsten Hädrich
- Institute of Forensic Medicine, University of Leipzig, Faculty of Medicine, Leipzig, Germany
| | - Holger Koch
- Translational Centre for Regenerative Medicine, University of Leipzig, Faculty of Medicine, Leipzig, Germany
| | - Robert Möbius
- Institute of Anatomy, University of Leipzig, Faculty of Medicine, Leipzig, Germany
| | - Gundula Schulze-Tanzil
- Department of Anatomy, Nuremberg Hospital Medical School, Paracelsus Medical University, Nuremburg, Germany and Salzburg, Austria
| | - Holger A Scheidt
- Institute of Medical Physics and Biophysics, University of Leipzig, Faculty of Medicine, Leipzig, Germany
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Engineering Tendon: Scaffolds, Bioreactors, and Models of Regeneration. Stem Cells Int 2015; 2016:3919030. [PMID: 26839559 PMCID: PMC4709784 DOI: 10.1155/2016/3919030] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2015] [Accepted: 09/20/2015] [Indexed: 12/23/2022] Open
Abstract
Tendons bridge muscle and bone, translating forces to the skeleton and increasing the safety and efficiency of locomotion. When tendons fail or degenerate, there are no effective pharmacological interventions. The lack of available options to treat damaged tendons has created a need to better understand and improve the repair process, particularly when suitable autologous donor tissue is unavailable for transplantation. Cells within tendon dynamically react to loading conditions and undergo phenotypic changes in response to mechanobiological stimuli. Tenocytes respond to ultrastructural topography and mechanical deformation via a complex set of behaviors involving force-sensitive membrane receptor activity, changes in cytoskeletal contractility, and transcriptional regulation. Effective ex vivo model systems are needed to emulate the native environment of a tissue and to translate cell-matrix forces with high fidelity. While early bioreactor designs have greatly expanded our knowledge of mechanotransduction, traditional scaffolds do not fully model the topography, composition, and mechanical properties of native tendon. Decellularized tendon is an ideal scaffold for cultivating replacement tissue and modeling tendon regeneration. Decellularized tendon scaffolds (DTS) possess high clinical relevance, faithfully translate forces to the cellular scale, and have bulk material properties that match natural tissue. This review summarizes progress in tendon tissue engineering, with a focus on DTS and bioreactor systems.
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Sichting F, Steinke H, Wagner MFX, Fritsch S, Hädrich C, Hammer N. Quantification of material slippage in the iliotibial tract when applying the partial plastination clamping technique. J Mech Behav Biomed Mater 2015; 49:112-7. [DOI: 10.1016/j.jmbbm.2015.04.028] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 04/19/2015] [Accepted: 04/27/2015] [Indexed: 11/26/2022]
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Schiele NR, von Flotow F, Tochka ZL, Hockaday LA, Marturano JE, Thibodeau JJ, Kuo CK. Actin cytoskeleton contributes to the elastic modulus of embryonic tendon during early development. J Orthop Res 2015; 33:874-81. [PMID: 25721681 PMCID: PMC4889338 DOI: 10.1002/jor.22880] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2014] [Accepted: 02/20/2015] [Indexed: 02/04/2023]
Abstract
Tendon injuries are common and heal poorly. Strategies to regenerate or replace injured tendons are challenged by an incomplete understanding of normal tendon development. Our previous study showed that embryonic tendon elastic modulus increases as a function of developmental stage. Inhibition of enzymatic collagen crosslink formation abrogated increases in tendon elastic modulus at late developmental stages, but did not affect increases in elastic modulus of early stage embryonic tendons. Here, we aimed to identify potential contributors to the mechanical properties of these early stage embryonic tendons. We characterized tendon progenitor cells in early stage embryonic tendons, and the influence of actin cytoskeleton disruption on tissue elastic modulus. Cells were closely packed in embryonic tendons, and did not change in density during early development. We observed an organized network of actin filaments that seemed contiguous between adjacent cells. The actin filaments exhibited a crimp pattern with a period and amplitude that matched the crimp of collagen fibers at each developmental stage. Chemical disruption of the actin cytoskeleton decreased tendon tissue elastic modulus, measured by atomic force microscopy. Our results demonstrate that early developmental stage embryonic tendons possess a well organized actin cytoskeleton network that contributes significantly to tendon tissue mechanical properties.
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Affiliation(s)
- Nathan R. Schiele
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts
| | | | - Zachary L. Tochka
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts
| | - Laura A. Hockaday
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts
| | - Joseph E. Marturano
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts
| | | | - Catherine K. Kuo
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts,Cell, Molecular & Developmental Biology Program, Sackler School of Graduate Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts
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Mahalingam VD, Behbahani-Nejad N, Ronan EA, Olsen TJ, Smietana MJ, Wojtys EM, Wellik DM, Arruda EM, Larkin LM. Fresh versus frozen engineered bone-ligament-bone grafts for sheep anterior cruciate ligament repair. Tissue Eng Part C Methods 2014; 21:548-56. [PMID: 25397990 DOI: 10.1089/ten.tec.2014.0542] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Surgical intervention is often required to restore knee instability in patients with anterior cruciate ligament (ACL) injury. The most commonly used grafts for ACL reconstruction are tendon autografts or allografts. These current options, however, have shown failure rates requiring revision and continued instability in the long term. The mismatched biomechanical properties of the current tendon grafts compared with native ACL tissue are thought to contribute to these poor outcomes and potential risk of early onset osteoarthritis. As a possible solution to these issues, our laboratory has fabricated tissue-engineered ligament constructs that exhibit structural and functional properties similar to those of native ACL tissue after 6 months implantation. In addition, these tissue-engineered grafts achieve vascular and neural development that exceeds those of patellar tendon grafts. However, the utility of our tissue-engineered grafts is limited by the labor-intensive method required to produce the constructs and the need to use the constructs fresh, directly from the cell culturing system. Ideally, these constructs would be fabricated and stored until needed. Thus, in this study, we investigated the efficacy of freezing our tissue-engineered constructs as a method of preservation before use for ACL reconstruction. We hypothesized that frozen constructs would have similar histological and biomechanical outcomes compared with our fresh model. Our results showed that 6 months postimplantation as an ACL replacement graft, both our tissue-engineered fresh and frozen grafts demonstrated similar mechanical and histological outcomes, indicating that freezing is a suitable method for preserving and storing our graft before ACL reconstruction. The ability to use frozen constructs significantly increases the versatility of our graft technology expanding the clinical utility of our graft.
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Affiliation(s)
- Vasudevan D Mahalingam
- 1Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Nilofar Behbahani-Nejad
- 1Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Elizabeth A Ronan
- 1Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Tyler J Olsen
- 2Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan
| | - Michael J Smietana
- 3Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan
| | - Edward M Wojtys
- 4Medsport Sports Medicine Program, Orthopaedic Surgery, University of Michigan, Ann Arbor, Michigan
| | - Deneen M Wellik
- 5Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, Michigan.,6Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Ellen M Arruda
- 2Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan.,3Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan.,7Program in Macromolecular Science and Engineering, University of Michigan, Ann Arbor, Michigan
| | - Lisa M Larkin
- 1Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan.,3Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan
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