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Shan X, Otsuka S, Okubo T, Takeuchi T, Fukushige K, Naito M. Assessing site-specificity of the biomechanical properties of hamstring aponeuroses using MyotonPRO: A cadaveric study. Clin Biomech (Bristol, Avon) 2024; 114:106230. [PMID: 38493724 DOI: 10.1016/j.clinbiomech.2024.106230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 03/11/2024] [Accepted: 03/12/2024] [Indexed: 03/19/2024]
Abstract
BACKGROUND Hamstring muscles are the most frequently reported sites of muscle strain injuries, especially near the bi-articular muscles' myotendinous junction, where aponeurosis provides a connective tissue network linking muscle fibers to the tendon. This study aimed to investigate the reliability and site-specific differences of hamstring aponeuroses under different conditions (formalin and urea) using MyotonPRO. METHODS Eight hamstring muscle groups were dissected from four human cadavers (two males and two females) aged 83-93 years. Measurements of the mechanical properties of the aponeuroses from the superficial and deep regions of biceps femoris long head, semitendinosus, and semimembranosus (after formalin solution immersion) were done using MyotonPRO (intra-rater reliability was examined within a 24-h interval), following which the hamstring aponeuroses were measured using a similar procedure after urea solution immersion. FINDINGS Test-retest (intra-rater) results revealed that the MyotonPRO measurement of tone, stiffness, relaxation, and creep of cadaveric aponeuroses presented good to excellent reliability (ICC: 0.86 to 0.98). There were no significant differences in tone, stiffness, elasticity, relaxation, and creep among the six sites of hamstring aponeuroses under both formalin and urea conditions. Significant differences between formalin and urea conditions were found in the tone, stiffness, relaxation, and creep of hamstring aponeuroses (P < 0.05). INTERPRETATION These results suggested that the biomechanical properties of hamstring aponeuroses showed homogeneity between the sites using MyotonPRO. Urea solution could potentially neutralize the effect of formalin on the biomechanical properties of cadaveric muscle-aponeurosis-tendon units. The present findings might influence the design of subsequent cadaveric studies on hamstring muscle strains.
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Affiliation(s)
- Xiyao Shan
- Department of Anatomy, School of Medicine, Aichi Medical University, Nagakute, Aichi, Japan.
| | - Shun Otsuka
- Department of Anatomy, School of Medicine, Aichi Medical University, Nagakute, Aichi, Japan
| | - Tomohito Okubo
- Department of Anatomy, School of Medicine, Aichi Medical University, Nagakute, Aichi, Japan
| | - Takao Takeuchi
- Department of Anatomy, School of Medicine, Aichi Medical University, Nagakute, Aichi, Japan
| | - Kaori Fukushige
- Department of Anatomy, School of Medicine, Aichi Medical University, Nagakute, Aichi, Japan
| | - Munekazu Naito
- Department of Anatomy, School of Medicine, Aichi Medical University, Nagakute, Aichi, Japan
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Patzer TS, Kunz AS, Huflage H, Conrads N, Luetkens KS, Pannenbecker P, Ergün S, Herbst M, Herold S, Weber T, Bley TA, Grunz JP. Tomosynthesis of the Appendicular Skeleton on a Twin Robotic X-ray System: A Cadaveric Fracture Study. Acad Radiol 2024:S1076-6332(24)00090-4. [PMID: 38448327 DOI: 10.1016/j.acra.2024.02.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 02/11/2024] [Accepted: 02/13/2024] [Indexed: 03/08/2024]
Abstract
RATIONALE AND OBJECTIVES Aiming to offset image quality limitations in radiographs due to superimposition, this study investigates the diagnostic potential of appendicular skeleton tomosynthesis. MATERIALS AND METHODS Eight cadaveric extremities (four hands and feet) were examined employing the prototypical tomosynthesis mode of a twin robotic X-ray scanner. 12 protocols with varying sweep angles (10, 20 vs. 40°), frame rates (13 vs. 26 fps), and tube voltages (60 vs. 80 kV) were compared to radiographs. Four radiologists separately evaluated cortical and trabecular bone visualization and fracture patterns. Interreader reliability was assessed based on the intraclass correlation coefficient (ICC). RESULTS Radiation dose in radiography was 0.59 ± 0.20 dGy * cm2 versus 0.11 ± 0.00 to 2.46 ± 0.17 dGy * cm2 for tomosynthesis. Cortical bone display was inferior for radiographs compared to 40° and 20° tomosynthesis. Best results were ascertained for the 80 kV/40°/26 fps protocol. Trabecular bone depiction was also superior in tomosynthesis (p ≤ 0.009) and best with the 80 kV/10°/26 fps setting. Interreader reliability was moderate for cortical bone display (ICC 0.521, 95% confidence interval 0.356-0.641) and good for trabecular bone (0.759, 0.697-0.810). Diagnostic accuracy for articular involvement and multifragment situations was higher in tomosynthesis (93.8-100%/92.2-100%) vs. radiography (85.9%/82.8%.). Diagnostic confidence was also better in tomosynthesis (p ≤ 0.003). CONCLUSION Compared to radiography, tomosynthesis allows for superior assessability of cortical and trabecular bone and fracture morphology, especially at high framerates. Operating on a multipurpose X-ray system, tomosynthesis of the appendicular skeleton can be performed without additional scanner hardware.
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Affiliation(s)
- Theresa Sophie Patzer
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080 Würzburg, Germany.
| | - Andreas Steven Kunz
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080 Würzburg, Germany
| | - Henner Huflage
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080 Würzburg, Germany
| | - Nora Conrads
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080 Würzburg, Germany
| | - Karsten Sebastian Luetkens
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080 Würzburg, Germany
| | - Pauline Pannenbecker
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080 Würzburg, Germany
| | - Süleyman Ergün
- Institute of Anatomy and Cell Biology, University of Würzburg, Koellikerstraße 6, 97070 Würzburg, Germany
| | - Magdalena Herbst
- X-ray Products - Research & Development, Siemens Healthineers AG, Siemensstraße 3, 91301 Forchheim, Germany
| | - Sophia Herold
- X-ray Products - Research & Development, Siemens Healthineers AG, Siemensstraße 3, 91301 Forchheim, Germany
| | - Thomas Weber
- X-ray Products - Research & Development, Siemens Healthineers AG, Siemensstraße 3, 91301 Forchheim, Germany
| | - Thorsten Alexander Bley
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080 Würzburg, Germany
| | - Jan-Peter Grunz
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080 Würzburg, Germany
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Indermaur M, Casari D, Kochetkova T, Willie BM, Michler J, Schwiedrzik J, Zysset P. Does tissue fixation change the mechanical properties of dry ovine bone extracellular matrix? J Mech Behav Biomed Mater 2024; 150:106294. [PMID: 38128472 DOI: 10.1016/j.jmbbm.2023.106294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 07/01/2023] [Accepted: 12/02/2023] [Indexed: 12/23/2023]
Abstract
Tissue fixation is a prevalent method for bone conservation. Bone biopsies are typically fixed in formalin, dehydrated in ethanol, and infiltrated with polymethyl methacrylate (PMMA) Since some experiments can only be performed on fixed bone samples, it is essential to understand how fixation affects the measured material properties. The aim of this study was to quantify the influence of tissue fixation on the mechanical properties of cortical ovine bone at the extracellular matrix (ECM) level with state-of-the-art micromechanical techniques. A small section from the middle of the diaphysis of two ovine tibias (3.5 and 5.5 years old) was cut in the middle and polished on each side, resulting in a pair of mirrored surfaces. For each pair, one specimen underwent a fixation protocol involving immersion in formalin, dehydration with ethanol, and infiltration with PMMA. The other specimen (mirrored) was air-dried. Six osteons were selected in both pairs, which could be identified in both specimens. The influence of fixation on the mechanical properties was first analyzed using micropillar compression tests and nanoindentation in dry condition. Additionally, changes in the degree of mineralization were evaluated with Raman spectroscopy in both fixed and native bone ECM. Finally, micro tensile experiments were conducted in the 3.5-year fixed ovine bone ECM and compared to reported properties of unfixed dry ovine bone ECM. Interestingly, we found that tissue fixation does not alter the mechanical properties of ovine cortical bone ECM compared to experiments in dry state. However, animal age increases the degree of mineralization (p = 0.0159) and compressive yield stress (p = 0.041). Tissue fixation appears therefore as a valid conservation technique for investigating the mechanical properties of dehydrated bone ECM.
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Affiliation(s)
- Michael Indermaur
- ARTORG Center for Biomedical Engineering, University of Bern, Switzerland.
| | - Daniele Casari
- Swiss Federal Laboratories for Material Science and Technology, Empa, Thun, Switzerland
| | - Tatiana Kochetkova
- Swiss Federal Laboratories for Material Science and Technology, Empa, Thun, Switzerland
| | - Bettina M Willie
- Research Centre, Shriners Hospital for Children-Canada, Faculty of Dental Medicine and Oral Health Sciences, McGill University, Montreal, Canada
| | - Johann Michler
- Swiss Federal Laboratories for Material Science and Technology, Empa, Thun, Switzerland
| | - Jakob Schwiedrzik
- Swiss Federal Laboratories for Material Science and Technology, Empa, Thun, Switzerland
| | - Philippe Zysset
- ARTORG Center for Biomedical Engineering, University of Bern, Switzerland.
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Godbout C, Ryan G, Ramnaraign DJ, Hegner C, Desjardins S, Gagnon S, Bates BD, Whatley I, Schemitsch EH, Nauth A. Optimal delivery of endothelial progenitor cells in a rat model of critical-size bone defects. J Orthop Res 2024; 42:193-201. [PMID: 37416978 DOI: 10.1002/jor.25658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 05/21/2023] [Accepted: 07/01/2023] [Indexed: 07/08/2023]
Abstract
Nonunion and segmental bone defects are complex issues in orthopedic trauma. The use of endothelial progenitor cells (EPCs), as part of a cell-based therapy for bone healing is a promising approach. In preclinical studies, culture medium (CM) is commonly used to deliver EPCs to the defect site, which has the potential for immunogenicity in humans. The goal of this study was to find an effective and clinically translatable delivery medium for EPCs. Accordingly, this study compared EPCs delivered in CM, phosphate-buffered saline (PBS), platelet-poor plasma (PPP), and platelet-rich plasma (PRP) in a rat model of femoral critical-size defects. Fischer 344 rats (n = 35) were divided into six groups: EPC+CM, EPC+PBS, EPC+PPP, EPC+PRP, PPP alone, and PRP alone. A 5 mm mid-diaphyseal defect was created in the right femur and stabilized with a miniplate. The defect was filled with a gelatin scaffold impregnated with the corresponding treatment. Radiographic, microcomputed tomography and biomechanical analyses were performed. Overall, regardless of the delivery medium, groups that received EPCs had higher radiographic scores and union rates, higher bone volume, and superior biomechanical properties compared to groups treated with PPP or PRP alone. There were no significant differences in any outcomes between EPC subgroups or between PPP and PRP alone. These results suggest that EPCs are effective in treating segmental defects in a rat model of critical-size defects regardless of the delivery medium used. Consequently, PBS could be the optimal medium for delivering EPCs, given its low cost, ease of preparation, accessibility, noninvasiveness, and nonimmunogenic properties.
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Affiliation(s)
- Charles Godbout
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital-Unity Health Toronto, University of Toronto, Toronto, Ontario, Canada
| | - Gareth Ryan
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital-Unity Health Toronto, University of Toronto, Toronto, Ontario, Canada
| | - David J Ramnaraign
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital-Unity Health Toronto, University of Toronto, Toronto, Ontario, Canada
| | - Christian Hegner
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital-Unity Health Toronto, University of Toronto, Toronto, Ontario, Canada
| | - Sarah Desjardins
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital-Unity Health Toronto, University of Toronto, Toronto, Ontario, Canada
| | - Stéphane Gagnon
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital-Unity Health Toronto, University of Toronto, Toronto, Ontario, Canada
| | - Brent D Bates
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital-Unity Health Toronto, University of Toronto, Toronto, Ontario, Canada
| | - Ian Whatley
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital-Unity Health Toronto, University of Toronto, Toronto, Ontario, Canada
| | - Emil H Schemitsch
- Department of Surgery, Division of Orthopaedic Surgery, University of Western Ontario, London, Ontario, Canada
| | - Aaron Nauth
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital-Unity Health Toronto, University of Toronto, Toronto, Ontario, Canada
- Department of Surgery, Division of Orthopaedic Surgery, St. Michael's Hospital-Unity Health Toronto, University of Toronto, Toronto, Ontario, Canada
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Kochetkova T, Hanke MS, Indermaur M, Groetsch A, Remund S, Neuenschwander B, Michler J, Siebenrock KA, Zysset P, Schwiedrzik J. Composition and micromechanical properties of the femoral neck compact bone in relation to patient age, sex and hip fracture occurrence. Bone 2023; 177:116920. [PMID: 37769956 DOI: 10.1016/j.bone.2023.116920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 09/22/2023] [Accepted: 09/25/2023] [Indexed: 10/03/2023]
Abstract
Current clinical methods of bone health assessment depend to a great extent on bone mineral density (BMD) measurements. However, these methods only act as a proxy for bone strength and are often only carried out after the fracture occurs. Besides BMD, composition and tissue-level mechanical properties are expected to affect the whole bone's strength and toughness. While the elastic properties of the bone extracellular matrix (ECM) have been extensively investigated over the past two decades, there is still limited knowledge of the yield properties and their relationship to composition and architecture. In the present study, morphological, compositional and micropillar compression bone data was collected from patients who underwent hip arthroplasty. Femoral neck samples from 42 patients were collected together with anonymous clinical information about age, sex and primary diagnosis (coxarthrosis or hip fracture). The femoral neck cortex from the inferomedial region was analyzed in a site-matched manner using a combination of micromechanical testing (nanoindentation, micropillar compression) together with micro-CT and quantitative polarized Raman spectroscopy for both morphological and compositional characterization. Mechanical properties, as well as the sample-level mineral density, were constant over age. Only compositional properties demonstrate weak dependence on patient age: decreasing mineral to matrix ratio (p = 0.02, R2 = 0.13, 2.6 % per decade) and increasing amide I sub-peak ratio I∼1660/I∼1683 (p = 0.04, R2 = 0.11, 1.5 % per decade). The patient's sex and diagnosis did not seem to influence investigated bone properties. A clear zonal dependence between interstitial and osteonal cortical zones was observed for compositional and elastic bone properties (p < 0.0001). Site-matched microscale analysis confirmed that all investigated mechanical properties except yield strain demonstrate a positive correlation with the mineral fraction of bone. The output database is the first to integrate the experimentally assessed microscale yield properties, local tissue composition and morphology with the available patient clinical information. The final dataset was used for bone fracture risk prediction in-silico through the principal component analysis and the Naïve Bayes classification algorithm. The analysis showed that the mineral to matrix ratio, indentation hardness and micropillar yield stress are the most relevant parameters for bone fracture risk prediction at 70 % model accuracy (0.71 AUC). Due to the low number of samples, further studies to build a universal fracture prediction algorithm are anticipated with the higher number of patients (N > 200). The proposed classification algorithm together with the output dataset of bone tissue properties can be used for the future comparison of existing methods to evaluate bone quality as well as to form a better understanding of the mechanisms through which bone tissue is affected by aging or disease.
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Affiliation(s)
- Tatiana Kochetkova
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Thun, Switzerland.
| | - Markus S Hanke
- Department of Orthopedic Surgery, Inselspital, University of Bern, Switzerland
| | - Michael Indermaur
- ARTORG Center for Biomedical Engineering Research, University of Bern, Switzerland
| | - Alexander Groetsch
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Thun, Switzerland
| | - Stefan Remund
- Institute for Applied Laser, Photonics and Surface Technologies (ALPS), Bern University of Applied Sciences, Burgdorf, Switzerland
| | - Beat Neuenschwander
- Institute for Applied Laser, Photonics and Surface Technologies (ALPS), Bern University of Applied Sciences, Burgdorf, Switzerland
| | - Johann Michler
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Thun, Switzerland
| | - Klaus A Siebenrock
- Department of Orthopedic Surgery, Inselspital, University of Bern, Switzerland
| | - Philippe Zysset
- ARTORG Center for Biomedical Engineering Research, University of Bern, Switzerland
| | - Jakob Schwiedrzik
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Thun, Switzerland.
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Patzer TS, Kunz AS, Huflage H, Luetkens KS, Conrads N, Pannenbecker P, Jakuscheit A, Reppenhagen S, Ergün S, Bley TA, Grunz JP. Rotational alignment of the lower extremity in the presence of total knee endoprosthesis: Reproducibility of torsion analyses using ultra-low-dose photon-counting CT. Eur J Radiol 2023; 167:111055. [PMID: 37632998 DOI: 10.1016/j.ejrad.2023.111055] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 07/25/2023] [Accepted: 08/18/2023] [Indexed: 08/28/2023]
Abstract
PURPOSE Leg torsion analysis can provide valuable information in symptomatic patients after total knee arthroplasty. However, extensive beam-hardening and photon-starvation artifacts limit diagnostic assessability and dose reduction potential. For this study, we investigated the reproducibility of rotational measurements in ultra-low-dose photon-counting CT with spectral shaping via tin prefiltration. MATERIAL AND METHODS Employing a first-generation photon-counting CT, eight cadaveric specimens were examined with an established three-level scan protocol (hip: Sn 140, knee: Sn 100, ankle: Sn 100 kVp). In three body donors with unilateral knee endoprostheses, additional modified settings were applied (Sn 140 kVp at knee level). Protocols were executed with three dose levels (hip-knee-ankle, high-quality: 5.0-3.0-2.0 mGy, low-dose: 0.80-0.30-0.26 mGy, ultra-low-dose: 0.25-0.06-0.06 mGy). Six radiologists performed torsion analyses, additionally reporting their diagnostic confidence. Intraclass correlation coefficients (ICC) were calculated to assess interrater reliability. RESULTS No significant differences were ascertained for femoral (p = 0.330), tibial (p = 0.177), and overall leg rotation measurements (p = 0.358) among high-quality, low-dose, and ultra-low-dose protocols. Interrater reliability was excellent for torsion of the femur (ICC 0.915, 95% confidence interval 0.871-0.947), tibia (0.960, 0.938-0.976), and overall leg (0.967, 0.945-0.981). In specimens with total knee endoprostheses, absolute rotational measurements were unaffected by dose level and tube voltage despite superior diagnostic confidence on the ipsilateral and contralateral sides with modified settings (p < 0.001). CONCLUSIONS Combining the advantages of photon-counting CT and spectral shaping, reliable leg torsion analyses are feasible with ultra-low radiation exposure even in the presence of total knee endoprostheses.
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Affiliation(s)
- Theresa Sophie Patzer
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080 Würzburg, Germany.
| | - Andreas Steven Kunz
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080 Würzburg, Germany
| | - Henner Huflage
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080 Würzburg, Germany
| | - Karsten Sebastian Luetkens
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080 Würzburg, Germany
| | - Nora Conrads
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080 Würzburg, Germany
| | - Pauline Pannenbecker
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080 Würzburg, Germany
| | - Axel Jakuscheit
- Department of Orthopaedic Surgery, Koenig-Ludwig-Haus, University of Würzburg, Brettreichstrasse 11, 97074 Würzburg, Germany
| | - Stephan Reppenhagen
- Department of Orthopaedic Surgery, Koenig-Ludwig-Haus, University of Würzburg, Brettreichstrasse 11, 97074 Würzburg, Germany
| | - Süleyman Ergün
- Institute of Anatomy and Cell Biology, University of Würzburg, Koellikerstraße 6, 97070 Würzburg, Germany
| | - Thorsten Alexander Bley
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080 Würzburg, Germany
| | - Jan-Peter Grunz
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080 Würzburg, Germany
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Davis S, Zekonyte J, Karali A, Roldo M, Blunn G. Early Degenerative Changes in a Spontaneous Osteoarthritis Model Assessed by Nanoindentation. Bioengineering (Basel) 2023; 10:995. [PMID: 37760097 PMCID: PMC10525236 DOI: 10.3390/bioengineering10090995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 08/15/2023] [Accepted: 08/18/2023] [Indexed: 09/29/2023] Open
Abstract
Understanding early mechanical changes in articular cartilage (AC) and subchondral bone (SB) is crucial for improved treatment of osteoarthritis (OA). The aim of this study was to develop a method for nanoindentation of fresh, unfixed osteochondral tissue to assess the early changes in the mechanical properties of AC and SB. Nanoindentation was performed throughout the depth of AC and SB in the proximal tibia of Dunkin Hartley guinea pigs at 2 months, 3 months, and 2 years of age. The contralateral tibias were either histologically graded for OA or analyzed using immunohistochemistry. The results showed an increase in the reduced modulus (Er) in the deep zone of AC during early-stage OA (6.0 ± 1.75 MPa) compared to values at 2 months (4.04 ± 1.25 MPa) (*** p < 0.001). In severe OA (2-year) specimens, there was a significant reduction in Er throughout the superficial and middle AC zones, which correlated to increased ADAMTS 4 and 5 staining, and proteoglycan loss in these regions. In the subchondral bone, a 35.0% reduction in stiffness was observed between 2-month and 3-month specimens (*** p < 0.001). The severe OA age group had significantly increased SB stiffness of 36.2% and 109.6% compared to 2-month and 3-month-old specimens respectively (*** p < 0.001). In conclusion, this study provides useful information about the changes in the mechanical properties of both AC and SB during both early- and late-stage OA and indicates that an initial reduction in stiffness of the SB and an increase in stiffness in the deep zone of AC may precede early-stage cartilage degeneration.
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Affiliation(s)
- Sarah Davis
- School of Pharmacy and Biomedical Science, University of Portsmouth, Portsmouth PO1 2DT, UK; (M.R.); (G.B.)
- School of Mechanical and Design Engineering, University of Portsmouth, Portsmouth PO1 3DJ, UK; (J.Z.); (A.K.)
| | - Jurgita Zekonyte
- School of Mechanical and Design Engineering, University of Portsmouth, Portsmouth PO1 3DJ, UK; (J.Z.); (A.K.)
| | - Aikaterina Karali
- School of Mechanical and Design Engineering, University of Portsmouth, Portsmouth PO1 3DJ, UK; (J.Z.); (A.K.)
| | - Marta Roldo
- School of Pharmacy and Biomedical Science, University of Portsmouth, Portsmouth PO1 2DT, UK; (M.R.); (G.B.)
| | - Gordon Blunn
- School of Pharmacy and Biomedical Science, University of Portsmouth, Portsmouth PO1 2DT, UK; (M.R.); (G.B.)
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8
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Fan X, Lee KM, Jones MWM, Howard D, Sun AR, Crawford R, Prasadam I. Spatial distribution of elements during osteoarthritis disease progression using synchrotron X-ray fluorescence microscopy. Sci Rep 2023; 13:10200. [PMID: 37353503 PMCID: PMC10290122 DOI: 10.1038/s41598-023-36911-w] [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: 01/15/2023] [Accepted: 06/12/2023] [Indexed: 06/25/2023] Open
Abstract
The osteochondral interface is a thin layer that connects hyaline cartilage to subchondral bone. Subcellular elemental distribution can be visualised using synchrotron X-ray fluorescence microscopy (SR-XFM) (1 μm). This study aims to determine the relationship between elemental distribution and osteoarthritis (OA) progression based on disease severity. Using modified Mankin scores, we collected tibia plates from 9 knee OA patients who underwent knee replacement surgery and graded them as intact cartilage (non-OA) or degraded cartilage (OA). We used a tape-assisted system with a silicon nitride sandwich structure to collect fresh-frozen osteochondral sections, and changes in the osteochondral unit were defined using quantified SR-XFM elemental mapping at the Australian synchrotron's XFM beamline. Non-OA osteochondral samples were found to have significantly different zinc (Zn) and calcium (Ca) compositions than OA samples. The tidemark separating noncalcified and calcified cartilage was rich in zinc. Zn levels in OA samples were lower than in non-OA samples (P = 0.0072). In OA samples, the tidemark had less Ca than the calcified cartilage zone and subchondral bone plate (P < 0.0001). The Zn-strontium (Sr) colocalisation index was higher in OA samples than in non-OA samples. The lead, potassium, phosphate, sulphur, and chloride distributions were not significantly different (P > 0.05). In conclusion, SR-XFM analysis revealed spatial elemental distribution at the subcellular level during OA development.
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Affiliation(s)
- Xiwei Fan
- Centre for Biomedical Technologies, School of Mechanical, Medical and Process Engineering, Queensland University of Technology, 60 Musk Ave/Cnr. Blamey St, Kelvin Grove, QLD, 4059, Australia
| | - Kah Meng Lee
- Central Analytical Research Facility, Queensland University of Technology, Brisbane, 4059, Australia
| | - Michael W M Jones
- Central Analytical Research Facility, Queensland University of Technology, Brisbane, 4059, Australia
- School of Chemistry and Physics, Queensland University of Technology, Brisbane, 4000, Australia
| | - Daryl Howard
- Australian Synchrotron, Melbourne, 3168, Australia
| | - Antonia Rujia Sun
- Centre for Biomedical Technologies, School of Mechanical, Medical and Process Engineering, Queensland University of Technology, 60 Musk Ave/Cnr. Blamey St, Kelvin Grove, QLD, 4059, Australia
| | - Ross Crawford
- Centre for Biomedical Technologies, School of Mechanical, Medical and Process Engineering, Queensland University of Technology, 60 Musk Ave/Cnr. Blamey St, Kelvin Grove, QLD, 4059, Australia
- The Prince Charles Hospital, Brisbane, 4032, Australia
| | - Indira Prasadam
- Centre for Biomedical Technologies, School of Mechanical, Medical and Process Engineering, Queensland University of Technology, 60 Musk Ave/Cnr. Blamey St, Kelvin Grove, QLD, 4059, Australia.
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Patzer TS, Kunz AS, Huflage H, Luetkens KS, Conrads N, Gruschwitz P, Pannenbecker P, Ergün S, Bley TA, Grunz JP. Quantitative and qualitative image quality assessment in shoulder examinations with a first-generation photon-counting detector CT. Sci Rep 2023; 13:8226. [PMID: 37217553 DOI: 10.1038/s41598-023-35367-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 05/17/2023] [Indexed: 05/24/2023] Open
Abstract
Photon-counting detector (PCD) CT allows for ultra-high-resolution (UHR) examinations of the shoulder without requiring an additional post-patient comb filter to narrow the detector aperture. This study was designed to compare the PCD performance with a high-end energy-integrating detector (EID) CT. Sixteen cadaveric shoulders were examined with both scanners using dose-matched 120 kVp acquisition protocols (low-dose/full-dose: CTDIvol = 5.0/10.0 mGy). Specimens were scanned in UHR mode with the PCD-CT, whereas EID-CT examinations were conducted in accordance with the clinical standard as "non-UHR". Reconstruction of EID data employed the sharpest kernel available for standard-resolution scans (ρ50 = 12.3 lp/cm), while PCD data were reconstructed with both a comparable kernel (11.8 lp/cm) and a sharper dedicated bone kernel (16.5 lp/cm). Six radiologists with 2-9 years of experience in musculoskeletal imaging rated image quality subjectively. Interrater agreement was analyzed by calculation of the intraclass correlation coefficient in a two-way random effects model. Quantitative analyses comprised noise recording and calculating signal-to-noise ratios based on attenuation measurements in bone and soft tissue. Subjective image quality was higher in UHR-PCD-CT than in EID-CT and non-UHR-PCD-CT datasets (all p < 0.001). While low-dose UHR-PCD-CT was considered superior to full-dose non-UHR studies on either scanner (all p < 0.001), ratings of low-dose non-UHR-PCD-CT and full-dose EID-CT examinations did not differ (p > 0.99). Interrater reliability was moderate, indicated by a single measures intraclass correlation coefficient of 0.66 (95% confidence interval: 0.58-0.73; p < 0.001). Image noise was lowest and signal-to-noise ratios were highest in non-UHR-PCD-CT reconstructions at either dose level (p < 0.001). This investigation demonstrates that superior depiction of trabecular microstructure and considerable denoising can be realized without additional radiation dose by employing a PCD for shoulder CT imaging. Allowing for UHR scans without dose penalty, PCD-CT appears as a promising alternative to EID-CT for shoulder trauma assessment in clinical routine.
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Affiliation(s)
- Theresa Sophie Patzer
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Str. 6, 97080, Würzburg, Germany
| | - Andreas Steven Kunz
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Str. 6, 97080, Würzburg, Germany
| | - Henner Huflage
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Str. 6, 97080, Würzburg, Germany
| | - Karsten Sebastian Luetkens
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Str. 6, 97080, Würzburg, Germany
| | - Nora Conrads
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Str. 6, 97080, Würzburg, Germany
| | - Philipp Gruschwitz
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Str. 6, 97080, Würzburg, Germany
| | - Pauline Pannenbecker
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Str. 6, 97080, Würzburg, Germany
| | - Süleyman Ergün
- Institute of Anatomy and Cell Biology, University of Würzburg, Koellikerstr. 6, 97070, Würzburg, Germany
| | - Thorsten Alexander Bley
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Str. 6, 97080, Würzburg, Germany
| | - Jan-Peter Grunz
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Str. 6, 97080, Würzburg, Germany.
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Patzer TS, Kunz AS, Huflage H, Conrads N, Luetkens KS, Pannenbecker P, Paul MM, Ergün S, Bley TA, Grunz JP. Ultrahigh-Resolution Photon-Counting CT in Cadaveric Fracture Models: Spatial Frequency Is Not Everything. Diagnostics (Basel) 2023; 13:diagnostics13101677. [PMID: 37238160 DOI: 10.3390/diagnostics13101677] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 05/07/2023] [Accepted: 05/08/2023] [Indexed: 05/28/2023] Open
Abstract
In this study, the impact of reconstruction sharpness on the visualization of the appendicular skeleton in ultrahigh-resolution (UHR) photon-counting detector (PCD) CT was investigated. Sixteen cadaveric extremities (eight fractured) were examined with a standardized 120 kVp scan protocol (CTDIvol 10 mGy). Images were reconstructed with the sharpest non-UHR kernel (Br76) and all available UHR kernels (Br80 to Br96). Seven radiologists evaluated image quality and fracture assessability. Interrater agreement was assessed with the intraclass correlation coefficient. For quantitative comparisons, signal-to-noise-ratios (SNRs) were calculated. Subjective image quality was best for Br84 (median 1, interquartile range 1-3; p ≤ 0.003). Regarding fracture assessability, no significant difference was ascertained between Br76, Br80 and Br84 (p > 0.999), with inferior ratings for all sharper kernels (p < 0.001). Interrater agreement for image quality (0.795, 0.732-0.848; p < 0.001) and fracture assessability (0.880; 0.842-0.911; p < 0.001) was good. SNR was highest for Br76 (3.4, 3.0-3.9) with no significant difference to Br80 and Br84 (p > 0.999). Br76 and Br80 produced higher SNRs than all kernels sharper than Br84 (p ≤ 0.026). In conclusion, PCD-CT reconstructions with a moderate UHR kernel offer superior image quality for visualizing the appendicular skeleton. Fracture assessability benefits from sharp non-UHR and moderate UHR kernels, while ultra-sharp reconstructions incur augmented image noise.
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Affiliation(s)
- Theresa Sophie Patzer
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080 Würzburg, Germany
| | - Andreas Steven Kunz
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080 Würzburg, Germany
| | - Henner Huflage
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080 Würzburg, Germany
| | - Nora Conrads
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080 Würzburg, Germany
| | - Karsten Sebastian Luetkens
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080 Würzburg, Germany
| | - Pauline Pannenbecker
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080 Würzburg, Germany
| | - Mila Marie Paul
- Department of Orthopedic Trauma, Hand, Plastic and Reconstructive Surgery, University Hospital Würzburg, Oberdürrbacherstraße 6, 97080 Würzburg, Germany
| | - Süleyman Ergün
- Institute of Anatomy and Cell Biology, University of Würzburg, Koellikerstraße 6, 97070 Würzburg, Germany
| | - Thorsten Alexander Bley
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080 Würzburg, Germany
| | - Jan-Peter Grunz
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080 Würzburg, Germany
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11
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Adanty K, Bhagavathula KB, Tronchin O, Li DX, Rabey KN, Doschak MR, Adeeb S, Hogan J, Ouellet S, Plaisted TA, Satapathy SS, Romanyk DL, Dennison CR. The Mechanical Characterization and Comparions of Male and Female Calvaria Under Four-Point Bending Impacts. J Biomech Eng 2023; 145:1153590. [PMID: 36511109 DOI: 10.1115/1.4056459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Accepted: 12/02/2022] [Indexed: 12/15/2022]
Abstract
The circumstances in which we mechanically test and critically assess human calvarium tissue would find relevance under conditions encompassing real-world head impacts. These conditions include, among other variables, impact velocities, and strain rates. Compared to quasi-static loading on calvaria, there is less reporting on the impact loading of the calvaria and consequently, there are relatively fewer mechanical properties on calvaria at relevant impact loading rates available in the literature. The purpose of this work was to report on the mechanical response of 23 human calvarium specimens subjected to dynamic four-point bending impacts. Impacts were performed using a custom-built four-point impact apparatus at impact velocities of 0.86-0.89 m/s resulting in surface strain rates of 2-3/s-representative of strain rates observed in vehicle collisions and blunt impacts. The study revealed comparable effective bending moduli (11-15 GPa) to the limited work reported on the impact mechanics of calvaria in the literature, however, fracture bending stress (10-47 MPa) was relatively less. As expected, surface strains at fracture (0.21-0.25%) were less compared to studies that performed quasi-static bending. Moreover, the study revealed no significant differences in mechanical response between male and female calvaria. The findings presented in this work are relevant to many areas including validating surrogate skull fracture models in silico or laboratory during impact and optimizing protective devices used by civilians to reduce the risk of a serious head injury.
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Affiliation(s)
- Kevin Adanty
- Biomedical Instrumentation Laboratory, Donadeo Innovation Center for Engineering, Department of Mechanical Engineering, University of Alberta, 9211 116 Street NW, Edmonton, AB T6G 2E1, Canada
| | - Kapil B Bhagavathula
- Donadeo Innovation Center for Engineering, Department of Mechanical Engineering, University of Alberta, 9211 116 Street NW, Edmonton, AB T6G 2E1, Canada
| | - Olivia Tronchin
- Biomedical Instrumentation Laboratory, Donadeo Innovation Center for Engineering, Department of Mechanical Engineering, University of Alberta, 9211 116 Street NW, Edmonton, AB T6G 2E1, Canada
| | - David X Li
- Biomedical Instrumentation Laboratory, Donadeo Innovation Center for Engineering, Department of Mechanical Engineering, University of Alberta, 9211 116 Street NW, Edmonton, AB T6G 2E1, Canada
| | - Karyne N Rabey
- Department of Surgery, Division of Anatomy, University of Alberta, 2J2.00 WC Mackenzie Health Sciences Centre, 8440-112 Street NW, Edmonton, AB T6G 2R7, Canada; Department of Anthropology, Faculty of Arts, University of Alberta, 13-15 Tory Building, Edmonton, AB T6G 2H4, Canada
| | - Michael R Doschak
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Medical Sciences Building, 8613 114 Street NW, Edmonton, AB T6G 2H7, Canada
| | - Samer Adeeb
- Donadeo Innovation Centre for Engineering, Department of Civil and Environmental Engineering, University of Alberta, 9211 116 Street NW, Edmonton, AB T6G 1H9, Canada
| | - James Hogan
- Donadeo Innovation Center for Engineering, Department of Mechanical Engineering, University of Alberta, 9211 116 Street NW, Edmonton, AB T6G 2E1, Canada
| | - Simon Ouellet
- Defense Research and Development Canada, Valcartier Research Centre, 2459, de la, Route de la Bravoure, Quebec City, QC G3J 1X5, Canada
| | - Thomas A Plaisted
- U.S. Army Combat Capabilities Development Command, Army Research Laboratory, Aberdeen Proving Ground, MD 21005
| | - Sikhanda S Satapathy
- U.S. Army Combat Capabilities Development Command, Army Research Laboratory, Aberdeen Proving Ground, MD 21005
| | - Dan L Romanyk
- Donadeo Innovation Center for Engineering, Department of Mechanical Engineering, University of Alberta, 9211 116 Street NW, Edmonton, AB T6G 2E1, Canada; School of Dentistry, University of Alberta, 7-020 H Katz Group Centre for Pharmacy and Health Research, 87 Ave 114 Street, Edmonton, AB T6G 2E1, Canada
| | - Christopher R Dennison
- Biomedical Instrumentation Laboratory, Donadeo Innovation Center for Engineering, Department of Mechanical Engineering, University of Alberta, 9211 116 Street NW, Edmonton, AB T6G 2E1, Canada; Department of Mechanical Engineering, University of Victoria, Engineering Office Wing, Room 548 3800 Finnerty Road, Victoria, BC V8P 5C2, Canada
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12
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Portenard AC, Pegot A, Lievain L, Michelin P, Angot É, Beccari R, Duparc F, Auquit-Auckbur I. The distal dorsal intermetacarpal ligament: characterization of an overlooked structure-an anatomical study of 25 hands. Surg Radiol Anat 2023; 45:673-679. [PMID: 37017796 DOI: 10.1007/s00276-023-03139-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 03/22/2023] [Indexed: 04/06/2023]
Abstract
PURPOSE Exhaustive literature is available on the metacarpophalangeal joints of the long fingers, but the dorsal ligamentous structure overlaying the interosseous muscles and joining the metacarpal heads of the long fingers remains to be fully characterized. Previously, our surgical hand team observed a non-classically reported structure connecting the metacarpal heads of the long fingers, in the dorsal part of the intermetacarpal spaces. Therefore, the aim of this anatomical study was to characterize this ligamentous structure in terms of size, insertions, and anatomical position. METHODS Twenty-five hands were dissected for a total of 75 long finger intermetacarpal spaces. A ligamentous structure was exposed after cellular tissue excision and dorsal superficial fascia opening. The length and thickness were measured and anatomical position and insertions were studied. Histological analysis was performed on five specimens and ultrasound analysis in one healthy subject. RESULTS All 25 dissections revealed a dorsal ligamentous structure, hereafter named distal dorsal intermetacarpal ligament, which was inserted in the lateral tubercle of each adjacent long finger metacarpal head. This distal dorsal intermetacarpal ligament surrounded interosseous tendons. It was more proximal compared to oblique and transversal interosseous muscle fibers. Histological analysis confirmed the ligamentous nature of the structure. Ultrasound analysis showed that this structure was well identified under the dorsal aspect of the hand. CONCLUSION All dissections revealed a tense ligamentous structure between each metacarpal head of the long fingers. This was a constant structure meeting the definition of a ligament. The distal dorsal intermetacarpal ligament seems to stabilize the metacarpal heads at the second and fourth spaces by limiting hyperabduction.
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Affiliation(s)
- Anne-Carole Portenard
- Department of Plastic, Reconstructive and Hand Surgery, Rouen University Hospital, 37 Boulevard Gambetta, 76000, Rouen, France
| | - Alexandre Pegot
- Plastic and Aesthetic Surgery Department, Hôpital Privé Océane, 11 rue du Docteur-Audic, 56000, Vannes, France
| | - Ludovic Lievain
- Plastic and Aesthetic Surgery Department, Saint-Hilaire Clinic, 26 bis Boulevard Gambetta, 76044, Rouen Cedex, France
| | - Paul Michelin
- Department of Medical Imaging, Rouen University Hospital, 37 Boulevard Gambetta, 76000, Rouen, France
| | - Émilie Angot
- Department of Pathology, Normandy Centre for Genomic and Personalized Medicine, Rouen University Hospital, 76031, Rouen, France
| | - Roberto Beccari
- Department of Plastic, Reconstructive and Hand Surgery, Rouen University Hospital, 37 Boulevard Gambetta, 76000, Rouen, France
| | - Fabrice Duparc
- Laboratory of Anatomy, Faculty of Medicine and Pharmacy of Rouen, University of Normandy, 22 Boulevard Gambetta, 76000, Rouen, France.
| | - Isabelle Auquit-Auckbur
- Department of Plastic, Reconstructive and Hand Surgery, Rouen University Hospital, 37 Boulevard Gambetta, 76000, Rouen, France
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13
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Vial A, Costa L, Dosset P, Rosso P, Boutières G, Faklaris O, Haschke H, Milhiet PE, Doucet CM. Structure and mechanics of the human nuclear pore complex basket using correlative AFM-fluorescence superresolution microscopy. NANOSCALE 2023; 15:5756-5770. [PMID: 36786384 DOI: 10.1039/d2nr06034e] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Nuclear pore complexes (NPCs) are the only gateways between the nucleus and cytoplasm in eukaryotic cells. They restrict free diffusion to molecules below 5 nm while facilitating the active transport of selected cargoes, sometimes as large as the pore itself. This versatility implies an important pore plasticity. Recently, cryo-EM and AI-based protein modeling of human NPC revealed with acute precision how most constituents are arranged. But the basket, a fish trap-like structure capping the nucleoplasmic side of the pore, remains poorly resolved. Here by atomic force microscopy (AFM) coupled to single molecule localization microscopy (SMLM) we revealed that the basket is very soft and explores a large conformational landscape: apart from its canonical basket shape, it dives into the central pore channel or opens, with filaments reaching to the pore sides. Our observations highlight how this structure can adapt and let morphologically diverse cargoes shuttle through NPCs.
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Affiliation(s)
- Anthony Vial
- CBS (Centre de Biologie Structurale), Univ Montpellier, CNRS, INSERM, Montpellier, France.
| | - Luca Costa
- CBS (Centre de Biologie Structurale), Univ Montpellier, CNRS, INSERM, Montpellier, France.
| | - Patrice Dosset
- CBS (Centre de Biologie Structurale), Univ Montpellier, CNRS, INSERM, Montpellier, France.
| | - Pietro Rosso
- CBS (Centre de Biologie Structurale), Univ Montpellier, CNRS, INSERM, Montpellier, France.
| | - Gaëlle Boutières
- CBS (Centre de Biologie Structurale), Univ Montpellier, CNRS, INSERM, Montpellier, France.
| | - Orestis Faklaris
- MRI, Biocampus, University of Montpellier, CNRS, INSERM, Montpellier, France
| | | | | | - Christine M Doucet
- CBS (Centre de Biologie Structurale), Univ Montpellier, CNRS, INSERM, Montpellier, France.
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14
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Graf L, Arnold A, Blache S, Honegger F, Müller-Gerbl M, Stieger C. Effect of freezing and embalming of human cadaveric whole head specimens on bone conduction. Hear Res 2023; 429:108700. [PMID: 36680872 DOI: 10.1016/j.heares.2023.108700] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 12/23/2022] [Accepted: 01/12/2023] [Indexed: 01/15/2023]
Abstract
BACKGROUND AND AIMS Conserved specimens do not decay and therefore permit long-term experiments thereby overcoming limited access to fresh (frozen) temporal bones for studies on middle ear mechanics. We used a Thiel conservation method which is mainly based on a watery solution of salts. In contrast to pure Formalin, Thiel conservation aims to preserve the mechanical proprieties of human tissue. The aim of this study is to examine the effect of Thiel conservation on bone conduction in the same specimen before and after conservation. METHODS Nine ears of five defrosted whole heads were stimulated with a direct, electrically driven, bone anchored hearing system (Baha, Baha SuperPower). The motion produced by bone conduction stimulation was measured with a single point laser Doppler vibrometer (LDV) at the promontory, the ossicular chain, and the round window through a posterior tympanotomy. After the initial experiments, the entire whole heads were placed in Thiel solution. In order to enable direct comparison between fresh frozen and Thiel specimens, our Thiel conservation did not include intravascular and intrathecal perfusion. The measurements were repeated 3 and 12 months later. To determine the effect of freezing, defrosting, and embalming on the whole heads, CT scans were performed at different stages of the experimental procedure. Additionally, three extracted temporal bones were stimulated a Baha, motion of the promontory measured by LDV and embalmed in Thiel solution to investigate the direct impact of Thiel solution on the bone. RESULTS The averaged magnitude of motion on the promontory increased in whole head specimens by a mean of 10.3 dB after 3 months of Thiel embalming and stayed stable after 12 months. A similar effect was observed for motion at the tympanic membrane (+7.2 dB), the stapes (+9.5 dB), and the round window (+4.0 dB). In contrast to the whole head specimens, the motion of the extracted temporal bones did not change after 3 months of Thiel embalming (-0.04 dB in average). CT scans of the whole heads after conservation showed a notable brain volume loss mostly >50% as well as a remarkable change in the consistency and structure of the brain. Partial changes could already be observed before the Thiel embalming but after 1-2 days of defrosting. In an additional experiment, a substitution of brain mass and weight by Thiel fluid did not lead to new deterioration in sound transmission. In contrast, a frozen (non-defrosted) whole head showed a distinctively reduced magnitude of promontory motion before defrosting. DISCUSSION For our setup, the vibration of the ear due to bone conduction in the same whole head specimens significantly increased after Thiel conservation. Such an increase was not observed in extracted temporal bone specimens. Due to brain changes in the CT scans, we investigated the consequences of the brain volume changes and structure loss on the frozen brain before defrosting. The loss of brain volume alone could not explain the increase of ear vibrations, as we did not observe a difference when the volume was replaced with Thiel fluid. However, freezing and defrosting of the entire brain seems to have a major influence. Beside the destructive effect of freezing on the brain, the modified conservation method without perfusion changed the brain structure. In conclusion, bone conduction in whole heads depends on the physical condition of the brain, rather than on the conservation.
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Affiliation(s)
- Lukas Graf
- Department of ORL, University Hospital Basel, Hebelstrasse 10, Basel CH-4031, Switzerland
| | - Andreas Arnold
- Department of ORL, Spital Münsingen, Inselspital Bern and University of Bern, Switzerland
| | - Sandra Blache
- Department of Anatomy, University of Basel, Switzerland
| | - Flurin Honegger
- Department of ORL, University Hospital Basel, Hebelstrasse 10, Basel CH-4031, Switzerland
| | | | - Christof Stieger
- Department of ORL, University Hospital Basel, Hebelstrasse 10, Basel CH-4031, Switzerland.
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Qiu J, Liao Z, Xiang H, Li H, Yuan D, Jiang C, Xie J, Qin M, Li K, Zhao H. Effects of different preservation on the mechanical properties of cortical bone under quasi-static and dynamic compression. Front Bioeng Biotechnol 2023; 11:1082254. [PMID: 36911185 PMCID: PMC9995777 DOI: 10.3389/fbioe.2023.1082254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 02/09/2023] [Indexed: 02/25/2023] Open
Abstract
Introduction: Mechanical properties of biological tissue are important for numerical simulations. Preservative treatments are necessary for disinfection and long-term storage when conducting biomechanical experimentation on materials. However, few studies have been focused on the effect of preservation on the mechanical properties of bone in a wide strain rate. The purpose of this study was to evaluate the influence of formalin and dehydration on the intrinsic mechanical properties of cortical bone from quasi-static to dynamic compression. Methods: Cube specimens were prepared from pig femur and divided into three groups (fresh, formalin, and dehydration). All samples underwent static and dynamic compression at a strain rate from 10-3 s-1 to 103 s-1. The ultimate stress, ultimate strain, elastic modulus, and strain-rate sensitivity exponent were calculated. A one-way ANOVA test was performed to determine if the preservation method showed significant differences in mechanical properties under at different strain rates. The morphology of the macroscopic and microscopic structure of bones was observed. Results: The results show that ultimate stress and ultimate strain increased as the strain rate increased, while the elastic modulus decreased. Formalin fixation and dehydration did not affect elastic modulus significantly whereas significantly increased the ultimate strain and ultimate stress. The strain-rate sensitivity exponent was the highest in the fresh group, followed by the formalin group and dehydration group. Different fracture mechanisms were observed on the fractured surface, with fresh and preserved bone tending to fracture along the oblique direction, and dried bone tending to fracture along the axial direction. Discussion: In conclusion, preservation with both formalin and dehydration showed an influence on mechanical properties. The influence of the preservation method on material properties should be fully considered in developing a numerical simulation model, especially for high strain rate simulation.
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Affiliation(s)
- Jinlong Qiu
- Daping Hospital of Army Medical University, PLA, Chongqing, China
| | - Zhikang Liao
- Daping Hospital of Army Medical University, PLA, Chongqing, China
| | - Hongyi Xiang
- Daping Hospital of Army Medical University, PLA, Chongqing, China
| | - Haocheng Li
- Department of Medical Engineering, General Hospital of Central Theater Command, Wuhan, China
| | - Danfeng Yuan
- Daping Hospital of Army Medical University, PLA, Chongqing, China
| | - Chengyue Jiang
- School of Vehicle Engineering, Chongqing University of Technology, Chongqing, China
| | - Jingru Xie
- Daping Hospital of Army Medical University, PLA, Chongqing, China
| | - Mingxin Qin
- College of Biomedical Engineering, Army Medical University, PLA, Chongqing, China
| | - Kui Li
- Daping Hospital of Army Medical University, PLA, Chongqing, China
| | - Hui Zhao
- Daping Hospital of Army Medical University, PLA, Chongqing, China
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16
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Sun Y, Fu Y, Liu F, Zhang W, Ma H, Li Q, Zhou D, Fu B. Biomechanical tests and finite element analyses of pelvic stability using bilateral single iliac screws with different channels in lumbo-iliac fixation. Front Surg 2022; 9:1035614. [DOI: 10.3389/fsurg.2022.1035614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Accepted: 10/18/2022] [Indexed: 11/10/2022] Open
Abstract
BackgroundIn lumbo-iliac fixation, the iliac screw can be placed in several locations and directions. There is no uniform standard for the placement of a single iliac screw. Biomechanical tests and finite element analyses were used to compare the effect of bilateral single iliac screws with three channels on pelvic stability to determine the best channel.MethodsFive embalmed adult cadaver pelvic specimens were selected. An unstable Tile C1 pelvic injury model was established. Lumbo-iliac fixation for the treatment of left sacral Denis II fracture includes the following: three channels of bilateral, single iliac screws (channel A from posterior superior iliac spine (PSIS) to anterior inferior iliac spine (AIIS), channel B from 1 cm medial and 1 cm caudal of PSIS to AIIS, and channel C from 2 cm below PSIS to AIIS). Biomechanical testing was performed for stiffness evaluations. A finite element model was established to study the stress distribution of the model and the maximum von Mises stress of internal fixation.ResultsBiomechanical tests revealed that under vertical compression loading. The compressive stiffness fixed by channel B (246.15 ± 27.85 N/mm) was better than that fixed by channel A and channel C. Under torsional load, the torsional stiffness fixed by channel B (2.234 ± 0.223 N·m/°) was stronger than that fixed by channel A and channel C. However, there was no significant difference in terms of compressive and torsional stiffness between channel B and channel A (P > 0.05). Finite element analyses conformed that the maximum von Mises stress of the internal fixator fixed in channel B under the conditions of vertical, forwards bending, backwards extension, left bending, left rotating, and right bending (213.98 MPa, 338.96 MPa, 100.63 MPa, 297.06 MPa, 200.95 MPa and 284.75 MPa, respectively) was significantly lower than those fixed in channel A and channel C.ConclusionsThe construct stiffness of the channel from 1 cm medial and 1 cm caudal of PSIS to AIIS is better than that of the other two channels. This channel has the advantages of good biomechanical stability, small maximum von Mises stress of internal fixation.
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17
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Kunz AS, Patzer TS, Grunz JP, Luetkens KS, Hartung V, Hendel R, Fieber T, Genest F, Ergün S, Bley TA, Huflage H. Metal artifact reduction in ultra-high-resolution cone-beam CT imaging with a twin robotic X-ray system. Sci Rep 2022; 12:15549. [PMID: 36114270 PMCID: PMC9481547 DOI: 10.1038/s41598-022-19978-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Accepted: 09/07/2022] [Indexed: 11/23/2022] Open
Abstract
Cone-beam computed tomography (CBCT) has been shown to be a powerful tool for 3D imaging of the appendicular skeleton, allowing for detailed visualization of bone microarchitecture. This study was designed to compare artifacts in the presence of osteosynthetic implants between CBCT and multidetector computed tomography (MDCT) in cadaveric wrist scans. A total of 32 scan protocols with varying tube potential and current were employed: both conventional CBCT and MDCT studies were included with tube voltage ranging from 60 to 140 kVp as well as additional MDCT protocols with dedicated spectral shaping via tin prefiltration. Irrespective of scanner type, all examinations were conducted in ultra-high-resolution (UHR) scan mode. For reconstruction of UHR-CBCT scans an additional iterative metal artifact reduction algorithm was employed, an image correction tool which cannot be used in combination with UHR-MDCT. To compare applied radiation doses between both scanners, the volume computed tomography dose index for a 16 cm phantom (CTDIvol) was evaluated. Images were assessed regarding subjective and objective image quality. Without automatic tube current modulation or tube potential control, radiation doses ranged between 1.3 mGy (with 70 kVp and 50.0 effective mAs) and 75.2 mGy (with 140 kVp and 383.0 effective mAs) in UHR-MDCT. Using the pulsed image acquisition method of the CBCT scanner, CTDIvol ranged between 2.3 mGy (with 60 kVp and 0.6 mean mAs per pulse) and 61.0 mGy (with 133 kVp and 2.5 mean mAs per pulse). In essence, all UHR-CBCT protocols employing a tube potential of 80 kVp or more were found to provide superior overall image quality and artifact reduction compared to UHR-MDCT (all p < .050). Interrater reliability of seven radiologists regarding image quality was substantial for tissue assessment and moderate for artifact assessment with Fleiss kappa of 0.652 (95% confidence interval 0.618-0.686; p < 0.001) and 0.570 (95% confidence interval 0.535-0.606; p < 0.001), respectively. Our results demonstrate that the UHR-CBCT scan mode of a twin robotic X-ray system facilitates excellent visualization of the appendicular skeleton in the presence of metal implants. Achievable image quality and artifact reduction are superior to dose-comparable UHR-MDCT and even MDCT protocols employing spectral shaping with tin prefiltration do not achieve the same level of artifact reduction in adjacent soft tissue.
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Affiliation(s)
- Andreas Steven Kunz
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080, Würzburg, Germany.
| | - Theresa Sophie Patzer
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080, Würzburg, Germany
| | - Jan-Peter Grunz
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080, Würzburg, Germany
| | - Karsten Sebastian Luetkens
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080, Würzburg, Germany
| | - Viktor Hartung
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080, Würzburg, Germany
| | - Robin Hendel
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080, Würzburg, Germany
| | - Tabea Fieber
- Department of Trauma, Hand, Plastic and Reconstructive Surgery, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080, Würzburg, Germany
| | - Franca Genest
- Orthopedic Clinic König-Ludwig-Haus, Julius-Maximilians-Universität Würzburg, Brettreichstr. 11, 97070, Würzburg, Germany
| | - Süleyman Ergün
- Institute of Anatomy and Cell Biology, University of Würzburg, Koellikerstr. 6, 97070, Würzburg, Germany
| | - Thorsten Alexander Bley
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080, Würzburg, Germany
| | - Henner Huflage
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080, Würzburg, Germany
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Luetkens KS, Grunz JP, Paul MM, Huflage H, Conrads N, Patzer TS, Gruschwitz P, Ergün S, Bley TA, Kunz AS. One-stop-shop CT arthrography of the wrist without subject repositioning by means of gantry-free cone-beam CT. Sci Rep 2022; 12:14422. [PMID: 36002544 PMCID: PMC9402709 DOI: 10.1038/s41598-022-18395-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 08/10/2022] [Indexed: 11/16/2022] Open
Abstract
Modern cone-beam CT systems are capable of ultra-high-resolution 3D imaging in addition to conventional radiography and fluoroscopy. The combination of various imaging functions in a multi-use setup is particularly appealing for musculoskeletal interventions, such as CBCT arthrography (CBCTA). With this study, we aimed to investigate the feasibility of CBCTA of the wrist in a “one-stop-shop” approach with a gantry-free twin robotic scanner that does not require repositioning of subjects. Additionally, the image quality of CBCTA was compared to subsequent arthrograms on a high-end multidetector CT (MDCTA). Fourteen cadaveric wrists received CBCTA with four acquisition protocols. Specimens were then transferred to the CT suite for additional MDCTA. Dose indices ranged between 14.3 mGy (120 kVp/100 effective mAs; full-dose) and 1.0 mGy (70 kVp/41 effective mAs; ultra-low-dose) for MDCTA and between 17.4 mGy (80 kVp/2.5 mAs per pulse; full-dose) and 1.2 mGy (60 kVp/0.5 mAs per pulse; ultra-low-dose) for CBCTA. Subjective image quality assessment for bone, cartilage and ligamentous tissue was performed by seven radiologists. The interrater reliability was assessed by calculation of the intraclass correlation coefficient (ICC) based on a two-way random effects model. Overall image quality of most CBCTA was deemed suitable for diagnostic use in contrast to a considerable amount of non-diagnostic MDCTA examinations (38.8%). The depiction of bone, cartilage and ligaments in MDCTA with any form of dose reduction was inferior to any CBCTA scan with at least 0.6 mAs per pulse (all p < 0.001). Full-dose MDCTA and low-dose CBCTA were of equal quality for bone tissue visualization (p = 0.326), whereas CBCTA allowed for better depiction of ligaments and cartilage (both p < 0.001), despite merely one third of radiation exposure (MDCTA–14.3 mGy vs. CBCTA–4.5 mGy). Moderate to good interrater reliability was ascertained for the assessment all tissues (ICC 0.689–0.756). Overall median examination time for CBCTA was 5.4 min (4.8–7.2 min). This work demonstrates that substantial dose reduction can be achieved in CT arthrography of the wrist while maintaining diagnostic image quality by employing the cone-beam CT mode of a twin robotic X-ray system. The ability of the multi-use X-ray system to switch between fluoroscopy mode and 3D imaging allows for “one-stop-shop” CBCTA in minimal examination time without the need for repositioning.
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Affiliation(s)
- Karsten Sebastian Luetkens
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080, Würzburg, Germany.
| | - Jan-Peter Grunz
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080, Würzburg, Germany
| | - Mila Marie Paul
- Department of Orthopedic Trauma, Hand, Plastic and Reconstructive Surgery, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080, Würzburg, Germany
| | - Henner Huflage
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080, Würzburg, Germany
| | - Nora Conrads
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080, Würzburg, Germany
| | - Theresa Sophie Patzer
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080, Würzburg, Germany
| | - Philipp Gruschwitz
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080, Würzburg, Germany
| | - Süleyman Ergün
- Institute of Anatomy and Cell Biology, University of Würzburg, Koellikerstr. 6, 97070, Würzburg, Germany
| | - Thorsten Alexander Bley
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080, Würzburg, Germany
| | - Andreas Steven Kunz
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080, Würzburg, Germany
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Kochetkova T, Groetsch A, Indermaur M, Peruzzi C, Remund S, Neuenschwander B, Bellon B, Michler J, Zysset P, Schwiedrzik J. Assessing minipig compact jawbone quality at the microscale. J Mech Behav Biomed Mater 2022; 134:105405. [DOI: 10.1016/j.jmbbm.2022.105405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 07/21/2022] [Accepted: 07/26/2022] [Indexed: 10/16/2022]
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Hong DY, Berube ER, Strauch RJ. Ring finger metacarpal fracture iatrogenic rotation using an ulnar gutter splint: A cadaveric study. J Hand Ther 2022; 35:80-85. [PMID: 33279361 DOI: 10.1016/j.jht.2020.10.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 10/12/2020] [Accepted: 10/22/2020] [Indexed: 02/03/2023]
Abstract
STUDY DESIGN Cohort cadaveric study. INTRODUCTION Ring finger metacarpal fractures are often treated with ulnar gutter orthoses incorporating the ring and small fingers. Iatrogenic pronation of the distal metacarpal fragment may occur from overzealous orthotic "molding", resulting in a crossover deformity of the ring finger over the small finger. PURPOSE OF THE STUDY The goal of this cadaveric study is to determine whether including the middle finger in an ulnar gutter orthotic could lessen the chances of iatrogenic ring finger metacarpal fracture rotation. METHODS Transverse ring finger metacarpal shaft fractures were created in 24 cadaver hands. The ring and small fingers were then placed into an intrinsic plus position, simulating the application of an ulnar gutter orthotic. Weights of 2.5, 5, and 10 pounds were applied to the ring and small fingers to simulate iatrogenic-induced fracture pronation. The amount of rotational displacement at the fracture was measured, and the protocol was repeated, including the middle finger in the intrinsic plus position. Mann-Whitney-Wilcoxon test was used for statistical analysis. RESULTS There was an increase in distal fragment rotation with increasing weight. Fracture displacement was greater with the 2-finger position than the 3-finger at all weight levels; this reached statistical significance at 10 lbs (2.8 vs 1.8 mm). CONCLUSIONS Application of an ulnar gutter orthotic including only ring and small fingers can rotate the distal fragment of a ring finger metacarpal shaft fracture such that overlap could occur with the small finger. Including the middle finger in ulnar gutter splints will mitigate against the rotation of the ring finger metacarpal shaft fracture.
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Affiliation(s)
- Daniel Y Hong
- Columbia University Medical Center, New York City, NY, USA.
| | - Emma R Berube
- Columbia University Medical Center, New York City, NY, USA
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Luetkens KS, Huflage H, Kunz AS, Ritschl L, Herbst M, Kappler S, Ergün S, Goertz L, Pennig L, Bley TA, Gassenmaier T, Grunz JP. The effect of tin prefiltration on extremity cone-beam CT imaging with a twin robotic X-ray system. Radiography (Lond) 2021; 28:433-439. [PMID: 34716089 DOI: 10.1016/j.radi.2021.10.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 08/13/2021] [Accepted: 10/09/2021] [Indexed: 10/20/2022]
Abstract
INTRODUCTION While tin prefiltration is established in various CT applications, its value in extremity cone-beam CT relative to optimized spectra has not been thoroughly assessed thus far. This study aims to investigate the effect of tin filters in extremity cone-beam CT with a twin-robotic X-ray system. METHODS Wrist, elbow and ankle joints of two cadaveric specimens were examined in a laboratory setup with different combinations of prefiltration (copper, tin), tube voltage and current-time product. Image quality was assessed subjectively by five radiologists with Fleiss' kappa being computed to measure interrater agreement. To provide a semiquantitative criterion for image quality, contrast-to-noise ratios (CNR) were compared for standardized regions of interest. Volume CT dose indices were calculated for a 16 cm polymethylmethacrylate phantom. RESULTS Radiation dose ranged from 17.4 mGy in the clinical standard protocol without tin filter to as low as 0.7 mGy with tin prefiltration. Image quality ratings and CNR for tin-filtered scans with 100 kV were lower than for 80 kV studies with copper prefiltration despite higher dose (11.2 and 5.6 vs. 4.5 mGy; p < 0.001). No difference was ascertained between 100 kV scans with tin filtration and 60 kV copper-filtered scans with 75% dose reduction (subjective: p = 0.101; CNR: p = 0.706). Fleiss' kappa of 0.597 (95% confidence interval 0.567-0.626; p < 0.001) indicated moderate interrater agreement. CONCLUSION Considerable dose reduction is feasible with tin prefiltration, however, the twin-robotic X-ray system's low-dose potential for extremity 3D imaging is maximized with a dedicated low-kilovolt scan protocol in situations without extensive beam-hardening artifacts. IMPLICATIONS FOR PRACTICE Low-kilovolt imaging with copper prefiltration provides a superior trade-off between dose reduction and image quality compared to tin-filtered cone-beam CT scan protocols with higher tube voltage.
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Affiliation(s)
- K S Luetkens
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080 Würzburg, Germany.
| | - H Huflage
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080 Würzburg, Germany.
| | - A S Kunz
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080 Würzburg, Germany.
| | - L Ritschl
- X-ray Products - Research & Development, Siemens Healthcare GmbH, Siemensstraße 1, 91301, Forchheim, Germany.
| | - M Herbst
- X-ray Products - Research & Development, Siemens Healthcare GmbH, Siemensstraße 1, 91301, Forchheim, Germany.
| | - S Kappler
- X-ray Products - Research & Development, Siemens Healthcare GmbH, Siemensstraße 1, 91301, Forchheim, Germany.
| | - S Ergün
- Institute of Anatomy and Cell Biology, University of Würzburg, Koellikerstraße 6, 97070 Würzburg, Germany.
| | - L Goertz
- Institute for Diagnostic and Interventional Radiology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Straße 62, 50937 Cologne, Germany.
| | - L Pennig
- Institute for Diagnostic and Interventional Radiology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Straße 62, 50937 Cologne, Germany.
| | - T A Bley
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080 Würzburg, Germany.
| | - T Gassenmaier
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080 Würzburg, Germany.
| | - J-P Grunz
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080 Würzburg, Germany.
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Dose reduction potential in cone-beam CT imaging of upper extremity joints with a twin robotic x-ray system. Sci Rep 2021; 11:20176. [PMID: 34635787 PMCID: PMC8505435 DOI: 10.1038/s41598-021-99748-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 09/22/2021] [Indexed: 11/09/2022] Open
Abstract
Cone-beam computed tomography is a powerful tool for 3D imaging of the appendicular skeleton, facilitating detailed visualization of bone microarchitecture. This study evaluated various combinations of acquisition and reconstruction parameters for the cone-beam CT mode of a twin robotic x-ray system in cadaveric wrist and elbow scans, aiming to define the best possible trade-off between image quality and radiation dose. Images were acquired with different combinations of tube voltage and tube current-time product, resulting in five scan protocols with varying volume CT dose indices: full-dose (FD; 17.4 mGy), low-dose (LD; 4.5 mGy), ultra-low-dose (ULD; 1.15 mGy), modulated low-dose (mLD; 0.6 mGy) and modulated ultra-low-dose (mULD; 0.29 mGy). Each set of projection data was reconstructed with three convolution kernels (very sharp [Ur77], sharp [Br69], intermediate [Br62]). Five radiologists subjectively assessed the image quality of cortical bone, cancellous bone and soft tissue using seven-point scales. Irrespective of the reconstruction kernel, overall image quality of every FD, LD and ULD scan was deemed suitable for diagnostic use in contrast to mLD (very sharp/sharp/intermediate: 60/55/70%) and mULD (0/3/5%). Superior depiction of cortical and cancellous bone was achieved in FDUr77 and LDUr77 examinations (p < 0.001) with LDUr77 scans also providing favorable bone visualization compared to FDBr69 and FDBr62 (p < 0.001). Fleiss' kappa was 0.618 (0.594-0.641; p < 0.001), indicating substantial interrater reliability. In this study, we demonstrate that considerable dose reduction can be realized while maintaining diagnostic image quality in upper extremity joint scans with the cone-beam CT mode of a twin robotic x-ray system. Application of sharper convolution kernels for image reconstruction facilitates superior display of bone microarchitecture.
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Evaluation of Ultra-High-Resolution Cone-Beam CT Prototype of Twin Robotic Radiography System for Cadaveric Wrist Imaging. Acad Radiol 2021; 28:e314-e322. [PMID: 32654956 DOI: 10.1016/j.acra.2020.06.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 06/12/2020] [Accepted: 06/13/2020] [Indexed: 01/14/2023]
Abstract
RATIONALE AND OBJECTIVES Cone-beam CT (CBCT) applications possess potential for dose reduction in musculoskeletal imaging. This study evaluates the ultra-high-resolution CBCT prototype of a twin robotic X-ray system in wrist examinations compared to high-resolution multidetector CT (MDCT). MATERIALS AND METHODS Sixteen wrists of body donors were examined with the CBCT scan mode and a 384 slice MDCT system. Radiation-equivalent low-dose (CTDIvol(16cm) = 3.3 mGy) and full-dose protocols (CTDIvol(16cm) = 13.8 mGy) were used for both systems. Two observers assessed image quality on a seven-point Likert scale. In addition, software-assisted quantification of signal intensity fractions in cancellous bone was performed. Fewer pixels with intermediate signal intensity were considered to indicate superior depiction of bone microarchitecture. RESULTS Subjective image quality in CBCT was superior to dose equivalent MDCT with p ≤ 0.03 for full-dose and p < 0.001 for low-dose scans, respectively. Median Likert values were 7/7 (reader 1 / reader 2) in full-dose CBCT, 6/6 in full-dose MDCT, 5/6 in low-dose CBCT and 3/3 in low-dose MDCT. Intraclass correlation coefficient was 0.936 (95% confidence interval, 0.897-0.961; p < 0.001), indicating excellent reliability. Objective analysis displayed smaller fractions of "indecisive" pixels with intermediate signal intensity for full-dose CBCT (0.57 [interquartile range 0.13]) compared to full-dose MDCT (0.68 [0.21]), low-dose CBCT (0.72 [0.19]), and low-dose MDCT (0.80 [0.15]) studies. No significant difference was observed between low-dose CBCT and full-dose MDCT. CONCLUSION The new CBCT prototype provides superior image quality for trabecula and bone marrow in cadaveric wrist studies and enables dose reduction up to 75% compared to high-resolution MDCT.
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Graf L, Arnold A, Roushan K, Honegger F, Müller-Gerbl M, Stieger C. Effect of conservation method on ear mechanics for the same specimen. Hear Res 2020; 401:108152. [PMID: 33388646 DOI: 10.1016/j.heares.2020.108152] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 11/24/2020] [Accepted: 12/08/2020] [Indexed: 01/18/2023]
Abstract
BACKGROUND AND AIMS As an alternative to fresh temporal bones, Thiel conserved specimens can be used in the study of ear mechanics. Conserved temporal bones do not decay, permit long-term experiments and overcome problems with limited access to fresh (frozen) temporal bones. Air conduction motion of the tympanic membrane (TM), stapes (ST) and round window (RW) in Thiel specimens is similar to that of fresh specimens according to reports in the literature. Our study compares this motion directly before and after conservation for the same specimens. METHODS The magnitude of motion of TM, ST and RW elicited by acoustic stimulation via the external auditory canal was measured using single point laser Doppler vibrometry (LDV) accessed through a posterior tympanotomy. For the initial measurements (10 ears), fresh frozen whole heads were thawed for at least 24 h. Afterwards, the entire whole heads were embalmed according to the Thiel embalming method and measurements were repeated 3 and 12 months later. RESULTS The magnitudes of TM, ST and RW motion before and after Thiel conservation differed maximally 10 dB on average. A significant increase in TM motion was observed at low frequencies only after long term conservation (12 months). ST motions decreased significantly between 161 and 5300 Hz after 3 months of Thiel conservation. Over the same time period RW motions decreased significantly between 100 and 161 Hz and 489-788 Hz. The ST and RW motions across all measured frequencies were lower after 3 months by 5.7 dB and 7.1 dB, respectively, without further changes after 12 months of conservation. The mean phase shift between ST and RW motion was only 2.1° for frequencies below 450 Hz. DISCUSSION AND CONCLUSION Thiel embalming changes motion of TM after long term conservation. ST and RW motion changed mainly after short term conservation. The phase shifts close to 180° between ST and RW motion indicates that the cochlea was still filled with liquid without air bubbles. The results show that Thiel conserved specimens can be used as an alternative model to fresh frozen preparations with some limitations when studying mechanics of the normal human ear, for example, in implant design.
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Affiliation(s)
- Lukas Graf
- Department of ENT, University Basel Hospital, Hebelstrasse 10, 4031 Basel, Switzerland; Department of ENT, Kantonsspital Aarau, Switzerland
| | - Andreas Arnold
- Department of ENT, Spital Münsingen and University of Bern, Switzerland
| | - Kourosh Roushan
- Department of ENT, University Basel Hospital, Hebelstrasse 10, 4031 Basel, Switzerland
| | - Flurin Honegger
- Department of ENT, University Basel Hospital, Hebelstrasse 10, 4031 Basel, Switzerland
| | | | - Christof Stieger
- Department of ENT, University Basel Hospital, Hebelstrasse 10, 4031 Basel, Switzerland.
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Hosseinitabatabaei S, Kawalilak CE, McDonald MP, Kontulainen SA, Johnston JD. Distal radius sections offer accurate and precise estimates of forearm fracture load. Clin Biomech (Bristol, Avon) 2020; 80:105144. [PMID: 32829235 DOI: 10.1016/j.clinbiomech.2020.105144] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 06/08/2020] [Accepted: 08/10/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND Forearm fracture risk can be estimated via factor-of-risk: the ratio of applied impact force to forearm fracture load. Simple techniques are available for estimating impact force associated with a fall; estimating forearm fracture load is more challenging. Our aim was to assess whether failure load estimates of sections of the distal radius (acquired using High-Resolution peripheral Quantitative Computed Tomography and finite element modeling) offer accurate and precise estimates of forearm fracture load. METHODS We scanned a section of the distal radius of 19 cadaveric forearms (female, mean age 83.7, SD 8.3), and 34 women (75.0, 7.7). Sections were converted to finite element models and failure loads were acquired for different failure criteria. We assessed forearm fracture load using experimental testing simulating a fall on the outstretched hand. We used linear regression to derive relationships between ex vivo forearm fracture load and finite element derived distal radius failure load. We used derived regression coefficients to estimate forearm fracture load, and assessed explained variance and prediction error. We used root-mean-squared coefficients of variation to assess in vivo precision errors of estimated forearm fracture load. FINDINGS Failure load estimates of sections of the distal radius, used in conjunction with derived regression coefficients, explained 89-90% of the variance in experimentally-measured forearm fracture load with prediction errors <6.8% and precision errors <5.0%. INTERPRETATION Failure load estimates of distal radius sections can reliably estimate forearm fracture load experienced during a fall. Forearm fracture load estimates can be used to improve factor-of-risk predictions for forearm fracture.
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Affiliation(s)
- Seyedmahdi Hosseinitabatabaei
- Division of Biomedical Engineering, College of Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, SK S7N 5A9, Canada
| | - Chantal E Kawalilak
- Department of Mechanical Engineering, College of Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, SK S7N 5A9, Canada
| | - Matthew P McDonald
- Department of Mechanical Engineering, College of Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, SK S7N 5A9, Canada
| | - Saija A Kontulainen
- Division of Biomedical Engineering, College of Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, SK S7N 5A9, Canada; College of Kinesiology, University of Saskatchewan, 87 Campus Drive, Saskatoon, SK S7N 5B2, Canada
| | - James D Johnston
- Division of Biomedical Engineering, College of Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, SK S7N 5A9, Canada; Department of Mechanical Engineering, College of Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, SK S7N 5A9, Canada.
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Grunz JP, Weng AM, Kunz AS, Veyhl-Wichmann M, Schmitt R, Gietzen CH, Pennig L, Herz S, Ergün S, Bley TA, Gassenmaier T. 3D cone-beam CT with a twin robotic x-ray system in elbow imaging: comparison of image quality to high-resolution multidetector CT. Eur Radiol Exp 2020; 4:52. [PMID: 32895778 PMCID: PMC7477066 DOI: 10.1186/s41747-020-00177-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 07/03/2020] [Indexed: 02/07/2023] Open
Abstract
Background Elbow imaging is challenging with conventional multidetector computed tomography (MDCT), while cone-beam CT (CBCT) provides superior options. We compared intra-individually CBCT versus MDCT image quality in cadaveric elbows. Methods A twin robotic x-ray system with new CBCT mode and a high-resolution clinical MDCT were compared in 16 cadaveric elbows. Both systems were operated with a dedicated low-dose (LD) protocol (equivalent volume CT dose index [CTDIvol(16 cm)] = 3.3 mGy) and a regular clinical scan dose (RD) protocol (CTDIvol(16 cm) = 13.8 mGy). Image quality was evaluated by two radiologists (R1 and R2) on a seven-point Likert scale, and estimation of signal intensity in cancellous bone was conducted. Wilcoxon signed-rank tests and intraclass correlation coefficient (ICC) statistics were used. Results The CBCT prototype provided superior subjective image quality compared to MDCT scans (for RD, p ≤ 0.004; for LD, p ≤ 0.001). Image quality was rated very good or excellent in 100% of the cases by both readers for RD CBCT, 100% (R1) and 93.8% (R2) for LD CBCT, 62.6% and 43.8% for RD MDCT, and 0.0% and 0.0% for LD MDCT. Single-measure ICC was 0.95 (95% confidence interval 0.91–0.97; p < 0.001). Software-based assessment supported subjective findings with less “undecided” pixels in CBCT than dose-equivalent MDCT (p < 0.001). No significant difference was found between LD CBCT and RD MDCT. Conclusions In cadaveric elbow studies, the tested cone-beam CT prototype delivered superior image quality compared to high-end multidetector CT and showed a potential for considerable dose reduction.
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Affiliation(s)
- Jan-Peter Grunz
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080, Würzburg, Germany.
| | - Andreas Max Weng
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080, Würzburg, Germany
| | - Andreas Steven Kunz
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080, Würzburg, Germany
| | - Maike Veyhl-Wichmann
- Institute of Anatomy and Cell Biology, University of Würzburg, Koellikerstraße 6, 97070, Würzburg, Germany
| | - Rainer Schmitt
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080, Würzburg, Germany
| | - Carsten Herbert Gietzen
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080, Würzburg, Germany
| | - Lenhard Pennig
- Institute for Diagnostic and Interventional Radiology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Straße 62, 50937, Cologne, Germany
| | - Stefan Herz
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080, Würzburg, Germany
| | - Süleyman Ergün
- Institute of Anatomy and Cell Biology, University of Würzburg, Koellikerstraße 6, 97070, Würzburg, Germany
| | - Thorsten Alexander Bley
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080, Würzburg, Germany
| | - Tobias Gassenmaier
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080, Würzburg, Germany
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Twin Robotic X-Ray System for 3D Cone-Beam CT of the Wrist: An Evaluation of Image Quality and Radiation Dose. AJR Am J Roentgenol 2020; 214:422-427. [DOI: 10.2214/ajr.19.21911] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Grunz JP, Kunz AS, Gietzen CH, Weng AM, Veyhl-Wichmann M, Ergün S, Schmitt R, Bley TA, Gassenmaier T. 3D cone-beam CT of the ankle using a novel twin robotic X-ray system: Assessment of image quality and radiation dose. Eur J Radiol 2019; 119:108659. [DOI: 10.1016/j.ejrad.2019.108659] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 09/03/2019] [Accepted: 09/04/2019] [Indexed: 12/29/2022]
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Kyphoplasty of Osteoporotic Fractured Vertebrae: A Finite Element Analysis about Two Types of Cement. BIOMED RESEARCH INTERNATIONAL 2019; 2019:9232813. [PMID: 31143778 PMCID: PMC6501275 DOI: 10.1155/2019/9232813] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Accepted: 04/09/2019] [Indexed: 12/11/2022]
Abstract
If conservative treatment of osteoporotic vertebral compression fractures fails, vertebro- or kyphoplasty is indicated. Usually, polymethylmethacrylate cement (PMMA) is applied coming along with many disadvantageous features. Aluminum-free glass-polyalkenoate cement (GPC) appears to be a benefit alternative material. This study aimed at comparing the mean stress values in human vertebrae after kyphoplasty with PMMA and GPC (IlluminOss™) at hand of a finite element analysis. Three models were created performing kyphoplasty using PMMA or IlluminOss™, respectively, at two native, human lumbar vertebrae (L4) while one remains intact. Finite element analysis was performed using CT-scans of every vertebra. Moreover the PMMA-treated vertebra was used as a model as analyses were executed using material data of PMMA and of GPC. The unimpaired, spongious bone showed potentials of 0.25 MPa maximally. After augmentation stress levels showed fivefold increase, rising from externally to internally, revealing stress peaks at the ventral border of the spinal canal. At central areas of cement 1 MPa is measured in both types of cement. Around these central areas the von Mises stress decreased about 25-50% (0.5-0.75 MPa). If workload of 500 N was applied, the stress appeared to be more centralized at the IlluminOss™-model, similar to the unimpaired. Considering the endplates the GPC model also closely resembles the unimpaired. Comparing the PMMA-treated vertebral body and the GPC-simulation, there is an obvious difference. While the PMMA-treated model showed a central stress peak of 5 MPa, the GPC-simulation of the same vertebral body presents lower stress of 1.2-2.5 MPa. Finite element analysis showed that IlluminOss™ (GPC), used in kyphoplasty of vertebral bodies, creates lower level stress and strain compared to standardly used PMMA, leading to lower stress concentrations on the cranial and caudal vertebral surface especially. GPC appears to own advantageous biological and clinical relevant features.
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Zhang G, Wang S, Xu S, Guan F, Bai Z, Mao H. The Effect of Formalin Preservation Time and Temperature on the Material Properties of Bovine Femoral Cortical Bone Tissue. Ann Biomed Eng 2019; 47:937-952. [DOI: 10.1007/s10439-019-02197-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 01/03/2019] [Indexed: 10/27/2022]
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Initial Assessment of a Prototype 3D Cone-Beam Computed Tomography System for Imaging of the Lumbar Spine, Evaluating Human Cadaveric Specimens in the Upright Position. Invest Radiol 2018; 53:714-719. [DOI: 10.1097/rli.0000000000000495] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Wright B, Ragan L, Niratisairak S, Høiseth A, Strømsøe K, Steen H, Brattgjerd JE. High correlation between mechanical properties and bone mineral parameters in embalmed femurs after long-term storage. Clin Biomech (Bristol, Avon) 2018; 59:136-142. [PMID: 30232057 DOI: 10.1016/j.clinbiomech.2018.09.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 09/10/2018] [Accepted: 09/11/2018] [Indexed: 02/07/2023]
Abstract
BACKGROUND Fresh frozen human femurs are considered "the gold standard" in biomechanical studies of hip fractures, resembling the in vivo situation mostly. A more readily available alternative is formalin embalmed femurs. However, to which extent formalin affects key features of bone; its mechanical properties, bone mineral content and their mutual relationship over time, remains unknown. Accordingly, we measured the mineral parameters and related them to the mechanical properties of formalin fixed femurs after long-term storage. METHODS 36 paired femurs from human donors, fixed in formalin and stored for a mean period of 4.6 (3.5-6) years. Quantitative CT was performed to measure the bone mineral density and mass at the mainly cortical mid shaft and the center of the mainly cancellous condyles. Each pair was subjected to local tests by three-point bending and screw pullout of the shaft and lateral punch and metaphyseal cube compression of the condyles. FINDINGS Neither mechanical nor bone mineral data were significantly correlated to storage time. Well-known associations for bone parameters with age and gender were retrieved. Maximum force of the cortical bone tests was highly correlated to the diaphyseal bone mass; (r = 0.80-0.87, p = 0.01), while maximum force of the cancellous bone tests correlated well to the density of the condylar bone; (r = 0.70, p = 0.01). INTERPRETATION Our results indicate that mechanical and bone mineral data and their mutual relationship are conserved in formalin fixed femurs even after long-term storage. Formalin fixed femurs may serve as an alternative to fresh frozen femurs in biomechanical testing.
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Affiliation(s)
- Bryan Wright
- Biomechanics Laboratory, Orthopaedic Division, Oslo University Hospital, Norway; Ringerike Hospital, Hønefoss, Norway.
| | - Lydia Ragan
- Division of Anatomy, Institute of Basic Medical Sciences, University of Oslo, Norway; Department of Physiotherapy, Faculty of Health Sciences, OsloMet - Oslo Metropolitan University, Norway
| | - Sanyalak Niratisairak
- Biomechanics Laboratory, Orthopaedic Division, Oslo University Hospital, Norway; Institute for Clinical Medicine, University of Oslo, Norway
| | - Arne Høiseth
- Biomechanics Laboratory, Orthopaedic Division, Oslo University Hospital, Norway
| | - Knut Strømsøe
- Biomechanics Laboratory, Orthopaedic Division, Oslo University Hospital, Norway
| | - Harald Steen
- Biomechanics Laboratory, Orthopaedic Division, Oslo University Hospital, Norway
| | - Jan Egil Brattgjerd
- Biomechanics Laboratory, Orthopaedic Division, Oslo University Hospital, Norway; Institute for Clinical Medicine, University of Oslo, Norway
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Leschinger T, Engel K, Brüggemann GP, Dederer V, Neiss WF, Scheyerer MJ, Müller LP, Wegmann K. Glass -polyalkenoate cement: An alternative material for kyphoplasty in osteoporotic vertebral compression fractures - An ex vivo study. J Mech Behav Biomed Mater 2018; 83:46-51. [PMID: 29677554 DOI: 10.1016/j.jmbbm.2018.03.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2017] [Revised: 02/27/2018] [Accepted: 03/05/2018] [Indexed: 12/27/2022]
Abstract
Adjacent vertebral body fracture is described as a risk after vertebroplasty and kyphoplasty. It may be true that this phenomenon is caused precisely because of the frequently used polymethylmethacrylate cement (PMMA), which shows a higher level of stiffness than bone material and may ultimately lead to shifting stress levels within the entire spine. The goal of the present study was to evaluate and compare the pressure distribution in the endplate of human vertebrae after kyphoplasty with PMMA and aluminum-free glass-polyalkenoate cement (gpc). For the present study, 8 fresh frozen human cadaveric vertebral bodies from the thoracolumbar junction were used. All vertebrae were augmented transpedicularly on one side with gpc and on the other side with PMMA. A loading of 600 N, 800 N and 1000 N was applied. In the data processing an individual region of interest (roi) was generated for each vertebra. The following parameters were determined for each roi: maximum force [N], maximum pressure [kPa], mean pressure [kPa], roi area [cm2]. We found significantly higher mean pressure values in the areas of the vertebrae augmented with PMMA, compared to the ones after augmentation with gpc (p = 0.012) when applying 1000 N. In the groups with lower forces there were no statistical relevant differences. The pressure distribution shows an advantage for gpc. A material, which does not create load concentration onto the cranial and caudal vertebral surface, could have major advantages concerning the risk of adjacent vertebral fractures. Thus the results of the 1000 N loading protocol suggest gpc being a possible alternative to ordinary PMMA cement, regarding its influence on stiffness in kyphoplasty. These and other general aspects like incorporation should be addressed and elaborated more detailed in further studies.
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Affiliation(s)
- Tim Leschinger
- Center for Orthopedic and Trauma Surgery, University Medical Center, Cologne, Germany; Cologne Center for Musculoskeletal Biomechanics, Medical Faculty, University of Cologne, Cologne, Germany.
| | - Karsten Engel
- Institute of Biomechanics and Orthopaedics, German Sport University Cologne, Cologne, Germany
| | - Gert Peter Brüggemann
- Cologne Center for Musculoskeletal Biomechanics, Medical Faculty, University of Cologne, Cologne, Germany; Institute of Biomechanics and Orthopaedics, German Sport University Cologne, Cologne, Germany
| | - Viktoria Dederer
- Center for Orthopedic and Trauma Surgery, University Medical Center, Cologne, Germany; Cologne Center for Musculoskeletal Biomechanics, Medical Faculty, University of Cologne, Cologne, Germany
| | | | - Max Joseph Scheyerer
- Center for Orthopedic and Trauma Surgery, University Medical Center, Cologne, Germany; Cologne Center for Musculoskeletal Biomechanics, Medical Faculty, University of Cologne, Cologne, Germany
| | - Lars Peter Müller
- Center for Orthopedic and Trauma Surgery, University Medical Center, Cologne, Germany; Cologne Center for Musculoskeletal Biomechanics, Medical Faculty, University of Cologne, Cologne, Germany
| | - Kilian Wegmann
- Center for Orthopedic and Trauma Surgery, University Medical Center, Cologne, Germany; Cologne Center for Musculoskeletal Biomechanics, Medical Faculty, University of Cologne, Cologne, Germany
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Zhang GJ, Yang J, Guan FJ, Chen D, Li N, Cao L, Mao H. Quantifying the Effects of Formalin Fixation on the Mechanical Properties of Cortical Bone Using Beam Theory and Optimization Methodology With Specimen-Specific Finite Element Models. J Biomech Eng 2017; 138:2538222. [PMID: 27447849 DOI: 10.1115/1.4034254] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2015] [Indexed: 11/08/2022]
Abstract
The effects of formalin fixation on bone material properties remain debatable. In this study, we collected 36 fresh-frozen cuboid-shaped cortical specimens from five male bovine femurs and immersed half of the specimens into 4% formalin fixation liquid for 30 days. We then conducted three-point bending tests and used both beam theory method and an optimization method combined with specimen-specific finite element (FE) models to identify material parameters. Through the optimization FE method, the formalin-fixed bones showed a significantly lower Young's modulus (-12%) compared to the fresh-frozen specimens, while no difference was observed using the beam theory method. Meanwhile, both the optimization FE and beam theory methods revealed higher effective failure strains for formalin-fixed bones compared to fresh-frozen ones (52% higher through the optimization FE method and 84% higher through the beam theory method). Hence, we conclude that the formalin fixation has a significant effect on bovine cortical bones at small, elastic, as well as large, plastic deformations.
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Does formalin fixation influence MSCT/CBCT accuracy? Surg Radiol Anat 2017; 40:31-37. [DOI: 10.1007/s00276-017-1908-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 08/05/2017] [Indexed: 10/19/2022]
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Cai X, Peralta L, Giron A, Helfen L, Olivier C, Peyrin F, Laugier P, Grimal Q. Cortical bone elasticity measured by resonant ultrasound spectroscopy is not altered by defatting and synchrotron X-ray imaging. J Mech Behav Biomed Mater 2017; 72:241-245. [DOI: 10.1016/j.jmbbm.2017.05.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 03/25/2017] [Accepted: 05/05/2017] [Indexed: 11/15/2022]
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Accuracy of 3D fluoro-navigated anterior transpedicular screws in the subaxial cervical spine: an experimental study on human specimens. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2017; 26:2934-2940. [DOI: 10.1007/s00586-017-5238-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 05/30/2017] [Accepted: 07/21/2017] [Indexed: 10/19/2022]
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Leuridan S, Goossens Q, Roosen J, Pastrav L, Denis K, Mulier M, Desmet W, Vander Sloten J. A biomechanical testing system to determine micromotion between hip implant and femur accounting for deformation of the hip implant: Assessment of the influence of rigid body assumptions on micromotions measurements. Clin Biomech (Bristol, Avon) 2017; 42:70-78. [PMID: 28110243 DOI: 10.1016/j.clinbiomech.2017.01.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 01/12/2017] [Accepted: 01/15/2017] [Indexed: 02/07/2023]
Abstract
BACKGROUND Accurate pre-clinical evaluation of the initial stability of new cementless hip stems using in vitro micromotion measurements is an important step in the design process to assess the new stem's potential. Several measuring systems, linear variable displacement transducer-based and other, require assuming bone or implant to be rigid to obtain micromotion values or to calculate derived quantities such as relative implant tilting. METHODS An alternative linear variable displacement transducer-based measuring system not requiring a rigid body assumption was developed in this study. The system combined advantages of local unidirectional and frame-and-bracket micromotion measuring concepts. The influence and possible errors that would be made by adopting a rigid body assumption were quantified. Furthermore, as the system allowed emulating local unidirectional and frame-and-bracket systems, the influence of adopting rigid body assumptions were also analyzed for both concepts. Synthetic and embalmed bone models were tested in combination with primary and revision implants. Single-legged stance phase loading was applied to the implant - bone constructs. FINDINGS Adopting a rigid body assumption resulted in an overestimation of mediolateral micromotion of up to 49.7μm at more distal measuring locations. Maximal average relative rotational motion was overestimated by 0.12° around the anteroposterior axis. Frontal and sagittal tilting calculations based on a unidirectional measuring concept underestimated the true tilting by an order of magnitude. INTERPRETATION Non-rigid behavior is a factor that should not be dismissed in micromotion stability evaluations of primary and revision femoral implants.
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Affiliation(s)
- Steven Leuridan
- Department of Mechanical Engineering, Biomechanics Division. KU Leuven, Celestijnenlaan 300c, Box 2419, 3001 Leuven, Belgium.
| | - Quentin Goossens
- Department of Mechanical Engineering, Smart Instrumentation, KU Leuven, Andreas Vesaliusstraat 13, 3000 Leuven, Belgium
| | - Jorg Roosen
- Department of Orthopedic Surgery, Leuven University Hospitals, Weligerveld 1, 3212 Pellenberg, Belgium
| | - Leonard Pastrav
- Department of Mechanical Engineering, Smart Instrumentation, KU Leuven, Andreas Vesaliusstraat 13, 3000 Leuven, Belgium
| | - Kathleen Denis
- Department of Mechanical Engineering, Smart Instrumentation, KU Leuven, Andreas Vesaliusstraat 13, 3000 Leuven, Belgium
| | - Michiel Mulier
- Department of Orthopedic Surgery, Leuven University Hospitals, Weligerveld 1, 3212 Pellenberg, Belgium
| | - Wim Desmet
- Department of Mechanical Engineering, PMA, KU Leuven, Celestijnenlaan 300c, 3001 Leuven, Belgium
| | - Jos Vander Sloten
- Department of Mechanical Engineering, Biomechanics Division. KU Leuven, Celestijnenlaan 300c, Box 2419, 3001 Leuven, Belgium
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Pascart T, Cortet B, Olejnik C, Paccou J, Migaud H, Cotten A, Delannoy Y, During A, Hardouin P, Penel G, Falgayrac G. Bone Samples Extracted from Embalmed Subjects Are Not Appropriate for the Assessment of Bone Quality at the Molecular Level Using Raman Spectroscopy. Anal Chem 2016; 88:2777-83. [DOI: 10.1021/acs.analchem.5b04400] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Tristan Pascart
- Lille University − ULCO, PMOI, EA 4490, 59000 Lille, France
- Department
of Rheumatology, Saint-Philibert Hospital, Lille University, 59160 Lomme, France
| | - Bernard Cortet
- Lille University − ULCO, PMOI, EA 4490, 59000 Lille, France
| | - Cecile Olejnik
- Lille University − ULCO, PMOI, EA 4490, 59000 Lille, France
| | - Julien Paccou
- Lille University − ULCO, PMOI, EA 4490, 59000 Lille, France
| | - Henri Migaud
- Lille University − ULCO, PMOI, EA 4490, 59000 Lille, France
| | - Anne Cotten
- Lille University − ULCO, PMOI, EA 4490, 59000 Lille, France
| | - Yann Delannoy
- Lille University − ULCO, PMOI, EA 4490, 59000 Lille, France
- Lille University, Taphonomy Unit, EA 7367, 59000 Lille, France
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Gruszka D, Herr R, Hely H, Hofmann P, Klitscher D, Hofmann A, Rommens PM. Impact of Different Screw Designs on Durability of Fracture Fixation: In Vitro Study with Cyclic Loading of Scaphoid Bones. PLoS One 2016; 11:e0145949. [PMID: 26741807 PMCID: PMC4704798 DOI: 10.1371/journal.pone.0145949] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 12/10/2015] [Indexed: 11/28/2022] Open
Abstract
PURPOSE The use of new headless compression screws (HCSs) for scaphoid fixation is growing, but the nonunion rate has remained constant. The aim of this study was to compare the stability of fixation resulting from four modern HCSs using a simulated fracture model to determine the optimal screw design(s). METHODS We tested 40 fresh-frozen cadaver scaphoids treated with the Acumed Acutrak 2 mini (AA), the KLS Martin HBS2 midi (MH), the Stryker TwinFix (ST) and the Synthes HCS 3.0 with a long thread (SH). The bones with simulated fractures and implanted screws were loaded uniaxially into flexion for 2000 cycles with a constant bending moment of 800 Nmm. The angulation of the fracture fragments was measured continuously. Data were assessed statistically using the univariate ANOVA test and linear regression analysis, and the significance level was set at p < 0.05. RESULTS The median angulation of bone fragments φ allowed by each screw was 0.89° for AA, 1.12° for ST, 1.44° for SH and 2.36° for MH. With regards to linear regression, the most reliable curve was achieved by MH, with a coefficient of determination of R2 = 0.827. This was followed by AA (R2 = 0.354), SH (R2 = 0.247) and ST (R2 = 0.019). Data assessed using an adapted ANOVA model showed no statistically significant difference (p = 0.291) between the screws. CONCLUSIONS The continuous development of HCSs has resulted in very comparable implants, and thus, at this time, other factors, such as surgeons' experience, ease of handling and price, should be taken into consideration.
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Affiliation(s)
- Dominik Gruszka
- Department of Orthopaedics and Traumatology, University Medical Center of Johannes Gutenberg University, Mainz, Germany
| | - Robert Herr
- Department of Orthopaedics and Traumatology, University Medical Center of Johannes Gutenberg University, Mainz, Germany
| | - Hans Hely
- Physics Division, RheinMain University of Applied Sciences, Wiesbaden, Germany
| | - Peer Hofmann
- Physics Division, RheinMain University of Applied Sciences, Wiesbaden, Germany
| | - Daniela Klitscher
- Department of Orthopaedics and Traumatology, University Medical Center of Johannes Gutenberg University, Mainz, Germany
| | - Alexander Hofmann
- Department of Orthopaedics and Traumatology, University Medical Center of Johannes Gutenberg University, Mainz, Germany
| | - Pol Maria Rommens
- Department of Orthopaedics and Traumatology, University Medical Center of Johannes Gutenberg University, Mainz, Germany
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Matsuki H, Shibano J, Kobayashi M, Nakatsuchi Y, Moriizumi T, Kato H. Elastic modulus of the femoral trochanteric region measured by scanning acoustic microscopy in elderly women. J Med Ultrason (2001) 2015; 42:303-13. [PMID: 26576781 DOI: 10.1007/s10396-014-0608-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 12/15/2014] [Indexed: 11/28/2022]
Abstract
PURPOSE We have devised a method that can obtain continuous detailed distributions of the elastic modulus along the measurement line in a non-decalcified specimen of human bone tissue. The aim of this study was to determine whether local variations exist in the distribution of mechanical properties within the trochanteric region of the femur of elderly females using a newly developed form of scanning acoustic microscopy (SAM) technology. METHODS Human proximal femurs were harvested from seven female cadavers aged between 67 and 88 years at death. Using data collected with SAM, the elastic modulus of cortical and trabecular bone tissue of the lateral and medial trochanter was calculated and statistically analyzed. RESULTS The longitudinal and transverse elastic moduli in cortical bone tissue of the lateral trochanter were found to be significantly lower than those of the medial trochanter in all specimens from individuals over age 70 (p < 0.05). Compared to that of the distal region, the longitudinal and transverse elastic moduli of trabecular bone tissue of the proximal region of the lateral trochanter were significantly lower in all specimens from individuals over age 80 (p < 0.05). CONCLUSION Our new method allows obtaining detailed distributions of the elastic modulus of bone tissue.
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Affiliation(s)
- Hiroyuki Matsuki
- Department of Orthopaedic Surgery, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano, 390-8621, Japan.
| | - Junichi Shibano
- Department of Mechanical Engineering, Kitami Institute of Technology, 165 Koen-cho, Kitami, Hokkaido, 090-8507, Japan
| | - Michiaki Kobayashi
- Department of Mechanical Engineering, Kitami Institute of Technology, 165 Koen-cho, Kitami, Hokkaido, 090-8507, Japan
| | - Yukio Nakatsuchi
- Department of Orthopaedic Surgery, Marunouchi Hospital, 1-7-45 Nagisa, Matsumoto, Nagano, 390-8601, Japan
| | - Tetsuji Moriizumi
- Department of Anatomy, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano, 390-8621, Japan
| | - Hiroyuki Kato
- Department of Orthopaedic Surgery, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano, 390-8621, Japan
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Mick E, Steinke H, Wolfskämpf T, Wieding J, Hammer N, Schulze M, Souffrant R, Bader R. Influence of short-term fixation with mixed formalin or ethanol solution on the mechanical properties of human cortical bone. CURRENT DIRECTIONS IN BIOMEDICAL ENGINEERING 2015. [DOI: 10.1515/cdbme-2015-0083] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
AbstractBone specimens obtained for biomechanical experiments are fresh-frozen for storage to slow down tissue degradation and autolysis in long-term storage. Alternatively, due to infectious risks related to the fresh tissues, fixative agents are commonly used. However, fixatives will likely change the mechanical properties of bone. Existing studies on this issue gave controversial results that are hardly comparable due to a variety of measurement approaches. For this reason, the influence of ethanol and a formalin-based fixative agent was evaluated on the mechanical properties of human cortical bone specimens by means of four-point-bending tests. 127 prismatic specimens with rectangular cross sections (2.5 x 2.5 x 20 mm3) were obtained from different regions of two fresh human femora (medial, lateral, dorsal, ventral). Specimens were either fixed in ethanol or in a mixed formalin solution or frozen following a given scheme. After two weeks of storage the samples were re-hydrated in isotonic saline and subsequently tested mechanically. The elastic bending modulus and ultimate bending strength were computed considering the actual dimensions of each specific specimen. For statistical analysis a one-way-ANOVA and an LSD post-hoc-test were performed. For ultimate bending strength no significant differences due to formalin or ethanol fixation, as compared to unfixed-fresh bone specimens could be found. And only for few cases significant differences in elastic bending modulus were observed when the two bones were evaluated separately. Since more differences of significant level due to the anatomical region of the samples were determined, the original location seems to have more influence on the evaluated mechanical properties than the method of (chemical) fixation. Consequently, ethanol and the mixed formalin solution can be recommended as a fixation agent for samples in biomechanical testing, if these samples are rinsed in isotonic saline prior to static mechanical testing.
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Affiliation(s)
- E. Mick
- 1Biomechanics and Implant Technology Research Lab, Department of Orthopaedics, University Medicine Rostock, Rostock, Germany
| | - H. Steinke
- 2Institute of Anatomy, Faculty of Medicine, University of Leipzig, Leipzig, Germany
| | - T. Wolfskämpf
- 2Institute of Anatomy, Faculty of Medicine, University of Leipzig, Leipzig, Germany
| | - J. Wieding
- 3Biomechanics and Implant Technology Research Lab, Department of Orthopaedics, University Medicine Rostock, Rostock, Germany
| | - N. Hammer
- 2Institute of Anatomy, Faculty of Medicine, University of Leipzig, Leipzig, Germany
| | - M. Schulze
- 4Department of Anatomy, University Medicine Rostock, Rostock, Germany
| | - R. Souffrant
- 3Biomechanics and Implant Technology Research Lab, Department of Orthopaedics, University Medicine Rostock, Rostock, Germany
| | - R. Bader
- 3Biomechanics and Implant Technology Research Lab, Department of Orthopaedics, University Medicine Rostock, Rostock, Germany
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Leumann A, Valderrabano V, Hoechel S, Göpfert B, Müller-Gerbl M. Mineral density and penetration strength of the subchondral bone plate of the talar dome: high correlation and specific distribution patterns. J Foot Ankle Surg 2014; 54:17-22. [PMID: 25451205 DOI: 10.1053/j.jfas.2014.09.035] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Indexed: 02/03/2023]
Abstract
The subchondral bone plate plays an important role in stabilizing the osteochondral joint unit and in the pathomechanism of osteochondral lesions and osteoarthritis. The objective of the present study was to measure the mineral density distribution and subchondral bone plate penetration strength of the talar dome joint facet to display and compare the specific distribution patterns. Ten cadaver specimens were used for computed tomography (CT) scans, from which densitograms were derived using CT-osteoabsorptiometry, and for mechanical indentation testing from which the penetration strength was obtained. Our results showed 2 different distribution patterns for mineral density and penetration strength. Of the 10 specimens, 6 (60%) showed bicentric maxima (anteromedially and anterolaterally), and 4 (40%) showed a monocentric maximum (either anteromedially or anterolaterally). A highly significant correlation (p < .0001) for both methods confirmed that the mineral density relied on local load characteristics. In conclusion, the biomechanical properties of the subchondral bone plate of the talar dome joint facet showed specific distribution patterns. CT-osteoabsorptiometry is a reliable method to display the mineral density distribution noninvasively. We recommend CT-osteoabsorptiometry for noninvasive analysis of the biomechanical properties of the subchondral bone plate in osteochondral joint reconstruction and the prevention and treatment of osteoarthritis and osteochondral lesions.
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Affiliation(s)
- André Leumann
- Institute of Anatomy, University of Basel, Basel, Switzerland; Orthopaedic Department, University Hospital of Basel, Basel, Switzerland.
| | | | | | - Beat Göpfert
- Laboratory of Biomechanics and Biocalorimetry, Clinical Morphology and Biomedical Engineering, University of Basel, Basel, Switzerland
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Benet A, Rincon-Torroella J, Lawton MT, González Sánchez JJ. Novel embalming solution for neurosurgical simulation in cadavers. J Neurosurg 2014; 120:1229-37. [DOI: 10.3171/2014.1.jns131857] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
Surgical simulation using postmortem human heads is one of the most valid strategies for neurosurgical research and training. The authors customized an embalming formula that provides an optimal retraction profile and lifelike physical properties while preventing microorganism growth and brain decay for neurosurgical simulations in cadavers. They studied the properties of the customized formula and compared its use with the standard postmortem processing techniques: cryopreservation and formaldehyde-based embalming.
Methods
Eighteen specimens were prepared for neurosurgical simulation: 6 formaldehyde embalmed, 6 cryopreserved, and 6 custom embalmed. The customized formula is a mixture of ethanol 62.4%, glycerol 17%, phenol 10.2%, formaldehyde 2.3%, and water 8.1%. After a standard pterional craniotomy, retraction profiles and brain stiffness were studied using an intracranial pressure transducer and monitor. Preservation time—that is, time that tissue remained in optimal condition—between specimen groups was also compared through periodical reports during a 48-hour simulation.
Results
The mean (± standard deviation) retraction pressures were highest in the formaldehyde group and lowest in the cryopreserved group. The customized formula provided a mean retraction pressure almost 3 times lower than formaldehyde (36 ± 3 vs 103 ± 14 mm Hg, p < 0.01) and very similar to cryopreservation (24 ± 6 mm Hg, p < 0.01). For research purposes, preservation time in the cryopreserved group was limited to 4 hours and was unlimited for the customized and formaldehyde groups for the duration of the experiment.
Conclusions
The customized embalming solution described herein is optimal for allowing retraction and surgical maneuverability while preventing decay. The authors were able to significantly lower the formaldehyde content as compared with that in standard formulas. The custom embalming solution has the benefits from both cryopreservation (for example, biological brain tissue properties) and formaldehyde embalming (for example, preservation time and microorganism growth prevention) and minimizes their drawbacks, that is, rapid decay in the former and stiffness in the latter. The presented embalming formula provides an important advance for neurosurgical simulations in research and teaching.
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Affiliation(s)
- Arnau Benet
- 1Skull Base and Cerebrovascular Laboratory, Department of Neurosurgery, University of California, San Francisco, California; and
| | | | - Michael T. Lawton
- 1Skull Base and Cerebrovascular Laboratory, Department of Neurosurgery, University of California, San Francisco, California; and
| | - J. J. González Sánchez
- 1Skull Base and Cerebrovascular Laboratory, Department of Neurosurgery, University of California, San Francisco, California; and
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Wegmann K, Engel K, Burkhart KJ, Ebinger M, Holz R, Brüggemann GP, Müller LP. Sequence of the Essex-Lopresti lesion--a high-speed video documentation and kinematic analysis. Acta Orthop 2014; 85:177-80. [PMID: 24479620 PMCID: PMC3967261 DOI: 10.3109/17453674.2014.887952] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND AND PURPOSE The pathomechanics of the Essex-Lopresti lesion are not fully understood. We used human cadavers and documented the genesis of the injury with high-speed cameras. METHODS 4 formalin-fixed cadaveric specimens of human upper extremities were tested in a prototype, custom-made, drop-weight test bench. An axial high-energy impulse was applied and the development of the lesion was documented with 3 high-speed cameras. RESULTS The high-speed images showed a transversal movement of the radius and ulna, which moved away from each other in the transversal plane during the impact. This resulted into a transversal rupture of the interosseous membrane, starting in its central portion, and only then did the radius migrate proximally and fracture. The lesion proceeded to the dislocation of the distal radio-ulnar joint and then to a full-blown Essex-Lopresti lesion. INTERPRETATION Our findings indicate that fracture of the radial head may be preceded by at least partial lesions of the interosseous membrane in the course of high-energy axial trauma.
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Affiliation(s)
- Kilian Wegmann
- Department of Orthopaedic and Trauma Surgery, University Medical Centre
| | - Karsten Engel
- Institute of Biomechanics and Orthopaedics, German Sport University Cologne, Cologne, Germany
| | - Klaus J Burkhart
- Department of Orthopaedic and Trauma Surgery, University Medical Centre
| | - Marc Ebinger
- Institute of Biomechanics and Orthopaedics, German Sport University Cologne, Cologne, Germany
| | - Robert Holz
- Institute of Biomechanics and Orthopaedics, German Sport University Cologne, Cologne, Germany
| | - Gert-Peter Brüggemann
- Institute of Biomechanics and Orthopaedics, German Sport University Cologne, Cologne, Germany
| | - Lars P Müller
- Department of Orthopaedic and Trauma Surgery, University Medical Centre
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Ethanol and formaldehyde fixation irreversibly alter bones' organic matrix. J Mech Behav Biomed Mater 2014; 29:252-8. [DOI: 10.1016/j.jmbbm.2013.09.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Revised: 08/21/2013] [Accepted: 09/02/2013] [Indexed: 11/21/2022]
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Biomechanical evaluation of the primary stability of pedicle screws after augmentation with an innovative bone stabilizing system. Arch Orthop Trauma Surg 2013; 133:1493-9. [PMID: 23995549 DOI: 10.1007/s00402-013-1842-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2013] [Indexed: 02/09/2023]
Abstract
INTRODUCTION In today's aging population, diminished bone quality often affects the outcome of surgical treatment. This occurs especially when surgical implants must be fixed to bone, as it occurs when lumbar fusion is performed with pedicle screws. Besides Polymethylmethacrylate (PMMA) injection, several techniques have been developed to augment pedicle screws. The aim of the current study was to evaluate the primary stability of an innovative system (IlluminOss™) for the augmentation of pedicle screws in an experimental cadaveric setup. IlluminOss™ is an innovative technology featuring cement with similar biochemical characteristics to aluminum-free glass-polyalkenoate cement (GPC). MATERIALS AND METHODS IlluminOss™ was inserted transpedicularly via a balloon/catheter system in 40 human cadaveric lumbar vertebrae. For comparability, each vertebra was treated bilaterally with pedicle screws, augmented and non-augmented. The maximum failure load during pull out test was documented by a universal material testing machine. RESULTS The results showed significantly higher failure loads for the augmented pedicle screws (Median 555.0 ± 261.0 N, Min. 220.0 N, Max. 1,500.0 N), compared to the native screws (Median 325.0 ± 312.1 N, Min. 29.0 N, Max. 1,400.0 N). CONCLUSIONS Based on these data, we conclude the IlluminOss™ system can be used to augment primary screw stability regarding axial traction, compared to native screws. The IlluminOss™ monomer offers ease of control for use in biological tissues. In contrast to PMMA, no relevant heat is generated during the hardening process and there is no risk of embolism. Further studies are necessary to evaluate the usefulness of the IlluminOss™ system in the in vivo augmentation of pedicle screws in the future.
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Mueller F, Hoechel S, Klaws J, Wirz D, Müller-Gerbl M. The subtalar and talonavicular joints: a way to access the long-term load intake using conventional CT-data. Surg Radiol Anat 2013; 36:463-72. [PMID: 24052199 DOI: 10.1007/s00276-013-1205-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2013] [Accepted: 09/05/2013] [Indexed: 01/23/2023]
Abstract
PURPOSE The aim of this study was to investigate the distribution of density of the subchondral bone plate within the articular surfaces of the subtalar and talonavicular joint regarding to its mineralisation and to verify whether a correlation to the mechanical bone strength exists. METHODS A total of 21 cadaverous lower leg specimens were investigated. Computed tomography osteo-absorptiometry (CT-OAM) was used to display the mineralisation of the subchondral bone plate analysing its density. The mechanical strength was measured by means of indentation testing. The distribution pattern was analysed regarding their dissemination with the main focus on number and location of their maxima. The correlation of both parameters was evaluated by linear regression. RESULTS The mineralisation and the mechanical strength were not distributed homogenously throughout the articular surfaces but showed unique and reproducible patterns. The range of absolute values for density and strength varied in between the samples and joint surfaces, but the number and location of the maxima evaluated by both methods showed to be concurring. The coefficient of correlation of both datasets ranged from 0.76 to 0.95 (median 0.88) and showed a linear dependency. CONCLUSIONS Density distribution and mechanical strength of the subchondral bone plate are significantly associated and can be seen as a mirror of the long-term load intake of a joint. It can be concluded that CT-OAM as a tool to visualize subchondral bone plate density distribution regarding to its mineralisation can be used to indirectly gain information about joint biomechanics in vivo by the use of conventional CT-data.
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Affiliation(s)
- Fabian Mueller
- Institute of Anatomy, University of Basel, Pestalozzistrasse 20, 4056, Basel, Switzerland
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Is distal locking necessary? A biomechanical investigation of intramedullary nailing constructs for intertrochanteric fractures. J Orthop Trauma 2013; 27:373-8. [PMID: 23249889 DOI: 10.1097/bot.0b013e31827cd5bd] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVES Unstable intertrochanteric fractures in the elderly occur frequently. Several studies have evaluated the biomechanical impact of distally locking long cephalomedullary nails under axial loading; however, the impact of torsional loading has not been investigated. The purpose of this study is to determine the rotational load to failure of unstable intertrochanteric fractures treated with long cephalomedullary nails, with and without distal interlocking. METHODS Eleven paired cadaveric femora treated with long cephalomedullary nails were randomized into 2 groups. Group 1 was left unlocked, whereas group 2 was distally locked. Osteotomies were completed to create unstable 4-part fractures. The femora were anatomically fixed proximally and distally and secured to the biomechanical testing machine to undergo internal rotation. Torque and rotational angle were measured until failure. RESULTS The locked group had a mean maximal torsional load of 57.9 ± 19.0 N·m and a mean rotational stiffness of 119.4 ± 35.7 N·m/rad. The femora treated with unlocked nails had a mean maximal torsional load of 29.1 ± 12.2 N·m and a mean rotational stiffness of 77.2 ± 31.3 N·m/rad. Distal locking resulted in a significant increase in maximal rotational load (P = 0.001) and rotational stiffness (P = 0.004) before failure. No significant difference was found in mean rotational angle at failure between groups (26.0 ± 9.6 degrees, P = 0.263). CONCLUSIONS Maximal torsional load to failure for the unlocked group is within the functional range of rotational loads experienced at the hip for an average adult. The results show that distal locking significantly increases rotational load to failure. The authors highly recommend routine use of distal interlocking screws during cephalomedullary nail placement in unstable intertrochanteric fractures.
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Steinke H, Lingslebe U, Böhme J, Slowik V, Shim V, Hädrich C, Hammer N. Deformation behavior of the iliotibial tract under different states of fixation. Med Eng Phys 2012; 34:1221-7. [DOI: 10.1016/j.medengphy.2011.12.009] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Revised: 12/09/2011] [Accepted: 12/14/2011] [Indexed: 01/14/2023]
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