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Troka M, Szepietowska K, Lubowiecka I. Self-organising maps in the analysis of strains of human abdominal wall to identify areas of similar mechanical behaviour. J Mech Behav Biomed Mater 2024; 156:106578. [PMID: 38781775 DOI: 10.1016/j.jmbbm.2024.106578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 03/05/2024] [Accepted: 05/08/2024] [Indexed: 05/25/2024]
Abstract
The study refers to the application of a type of artificial neural network called the Self-Organising Map (SOM) for the identification of areas of the human abdominal wall that behave in a similar mechanical way. The research is based on data acquired during in vivo tests using the digital image correlation technique (DIC). The mechanical behaviour of the human abdominal wall is analysed during changing intra-abdominal pressure. SOM allow to study simultaneously three variables in four time/load steps. The variables refer to the principal strains and their directions. SOM classifies all the abdominal surface data points into clusters that behave similarly in accordance with the 12 variables. The analysis of the clusters provides a better insight into abdominal wall deformation and its evolution under pressure than when observing a single mechanical variable. The presented results may provide a better understanding of the mechanics of the living human abdominal wall. It might be particularly useful when selecting proper implants as well as for the design of surgical meshes for the treatment of abdominal hernias, which would be mechanically compatible with identified regions of the human anterior abdominal wall, and possibly open the way for patient-specific solutions.
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Affiliation(s)
- Mateusz Troka
- Faculty of Civil and Environmental Engineering, Gdańsk University of Technology, Gdańsk, Poland
| | - Katarzyna Szepietowska
- Faculty of Civil and Environmental Engineering, Gdańsk University of Technology, Gdańsk, Poland
| | - Izabela Lubowiecka
- Faculty of Civil and Environmental Engineering, Gdańsk University of Technology, Gdańsk, Poland.
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Nessel R, Löffler T, Rinn J, Kallinowski F. Three-year follow-up of the grip concept: an open, prospective, observational registry study on biomechanically calculated abdominal wall repair for complex incisional hernias. Hernia 2024; 28:913-924. [PMID: 38761301 PMCID: PMC11249466 DOI: 10.1007/s10029-024-03064-2] [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: 01/14/2024] [Accepted: 04/28/2024] [Indexed: 05/20/2024]
Abstract
PURPOSE We studied the effectiveness of biomechanically calculated abdominal wall reconstructions for incisional hernias of varying complexity in an open, prospective observational registry trial. METHODS From July 1st, 2017 to December 31st, 2020, four hospitals affiliated with the University of Heidelberg recruited 198 patients with complex incisional hernias. Hernias were repaired using biomechanically calculated reconstructions and materials classified on their gripping force towards cyclic load. This approach determines the required strength preoperatively based on the hernia size, using the Critical Resistance to Impacts related to Pressure. The surgeon is supported in reliably determining the Gained Resistance, which is based on the mesh-defect-area-ratio, as well as other mesh and suture factors, and the tissue stability. Tissue stability is defined as a maximum distension of 1.5 cm upon a Valsalva maneuver. In complex cases, a CT scan of the abdomen can be used to assess unstable tissue areas both at rest and during Valsalva's maneuver. RESULTS Larger and stronger gripping meshes were required for more complex cases to achieve a durable repair, especially for larger hernia sizes. To achieve durable repairs, the number of fixation points increased while the mesh-defect area ratio decreased. Performing these repairs required more operating room time. The complication rate remained low. Less than 1% of recurrences and low pain levels were observed after 3 years. CONCLUSIONS Biomechanical stability, defined as the resistance to cyclic load, is crucial in preventing postoperative complications, including recurrences and chronic pain.
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Affiliation(s)
- R Nessel
- General, Visceral and Pediatric Surgery, Klinikum Am Gesundbrunnen, Am Gesundbrunnen 20‑26, 74078, Heilbronn, Germany
| | - T Löffler
- General and Visceral Surgery, GRN Hospital Eberbach, Scheuerbergstrasse 3, 69412, Eberbach, Germany
| | - J Rinn
- General and Visceral Surgery, KKB Hospital Bergstrasse, Viernheimer Strasse 2, 64646, Heppenheim, Germany
| | - F Kallinowski
- Hernia Center, General, Visceral and Transplantation Surgery, University Hospital Heidelberg, Im Neuenheimer Feld 420, 69120, Heidelberg, Germany.
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Gueroult P, Joppin V, Chaumoitre K, Di Bisceglie M, Masson C, Bege T. Linea alba 3D morphometric variability by CT scan exploration. Hernia 2024; 28:485-494. [PMID: 38177404 DOI: 10.1007/s10029-023-02939-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 11/26/2023] [Indexed: 01/06/2024]
Abstract
PURPOSE The width of the Linea alba, which is often gauged by inter-rectus distance, is a key risk factor for incisional hernia and recurrence. Previous studies provided limited descriptions with no consideration for width, location variability, or curvature. We aimed to offer a comprehensive 3D anatomical analysis of the Linea alba, emphasizing its variations across diverse demographics. METHODS Using open source software, 2D sagittal plane and 3D reconstructions were performed on 117 patients' CT scans. Linea alba length, curvature assessed by the sagitta (the longest perpendicular segment between xipho-pubic line and the Linea alba), and continuous width along the height were measured. RESULTS The Linea alba had a rhombus shape, with a maximum width at the umbilicus of 4.4 ± 1.9 cm and a larger width above the umbilicus than below. Its length was 37.5 ± 3.6 cm, which increased with body mass index (BMI) (p < 0.001), and was shorter in women (p < 0.001). The sagitta was 2.6 ± 2.2 cm, three times higher in the obese group (p < 0.001), majorated with age (p = 0.009), but was independent of gender (p = 0.212). Linea alba width increased with both age and BMI (p < 0.001-p = 0.002), being notably wider in women halfway between the umbilicus and pubis (p = 0.007). CONCLUSION This study provides an exhaustive 3D description of Linea alba's anatomical variability, presenting new considerations for curvature. This method provides a patient-specific anatomy description of the Linea alba. Further studies are needed to determine whether 3D reconstruction correlates with pathologies, such as hernias and diastasis recti.
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Affiliation(s)
- P Gueroult
- Laboratoire de Biomécanique Appliquée, Aix Marseille Univ, IFSTTAR UMR T24, Marseille, France.
- Service de chirurgie viscérale et endocrinienne, Angers University Hospital, Rue Larrey, 49933, CEDEX 9, Angers, France.
| | - V Joppin
- Laboratoire de Biomécanique Appliquée, Aix Marseille Univ, IFSTTAR UMR T24, Marseille, France
| | - K Chaumoitre
- Department of Medical Imaging, Aix Marseille Univ, North Hospital, APHM, Marseille, France
- Anthropologie Biologique UMR 7268ADES, Aix Marseille Univ, Marseille, France
| | - M Di Bisceglie
- Department of Medical Imaging, Aix Marseille Univ, North Hospital, APHM, Marseille, France
| | - C Masson
- Laboratoire de Biomécanique Appliquée, Aix Marseille Univ, IFSTTAR UMR T24, Marseille, France
| | - T Bege
- Laboratoire de Biomécanique Appliquée, Aix Marseille Univ, IFSTTAR UMR T24, Marseille, France
- Department of General Surgery, Aix Marseille Univ, North Hospital, APHM, Marseille, France
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Lin AC, Pirrung F, Niestrawska JA, Ondruschka B, Pinter G, Henyš P, Hammer N. Shape or size matters? Towards standard reporting of tensile testing parameters for human soft tissues: systematic review and finite element analysis. Front Bioeng Biotechnol 2024; 12:1368383. [PMID: 38600944 PMCID: PMC11005100 DOI: 10.3389/fbioe.2024.1368383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Accepted: 03/14/2024] [Indexed: 04/12/2024] Open
Abstract
Material properties of soft-tissue samples are often derived through uniaxial tensile testing. For engineering materials, testing parameters (e.g., sample geometries and clamping conditions) are described by international standards; for biological tissues, such standards do not exist. To investigate what testing parameters have been reported for tensile testing of human soft-tissue samples, a systematic review of the literature was performed using PRISMA guidelines. Soft tissues are described as anisotropic and/or hyperelastic. Thus, we explored how the retrieved parameters compared against standards for engineering materials of similar characteristics. All research articles published in English, with an Abstract, and before 1 January 2023 were retrieved from databases of PubMed, Web of Science, and BASE. After screening of articles based on search terms and exclusion criteria, a total 1,096 articles were assessed for eligibility, from which 361 studies were retrieved and included in this review. We found that a non-tapered shape is most common (209 of 361), followed by a tapered sample shape (92 of 361). However, clamping conditions varied and were underreported (156 of 361). As a preliminary attempt to explore how the retrieved parameters might influence the stress distribution under tensile loading, a pilot study was performed using finite element analysis (FEA) and constitutive modeling for a clamped sample of little or no fiber dispersion. The preliminary FE simulation results might suggest the hypothesis that different sample geometries could have a profound influence on the stress-distribution under tensile loading. However, no conclusions can be drawn from these simulations, and future studies should involve exploring different sample geometries under different computational models and sample parameters (such as fiber dispersion and clamping effects). Taken together, reporting and choice of testing parameters remain as challenges, and as such, recommendations towards standard reporting of uniaxial tensile testing parameters for human soft tissues are proposed.
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Affiliation(s)
- Alvin C. Lin
- Division of Macroscopic and Clinical Anatomy, Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
- Institute of Anatomy and Cell Biology, Paracelsus Medical University, Salzburg, Austria
| | - Felix Pirrung
- Division of Macroscopic and Clinical Anatomy, Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
| | - Justyna A. Niestrawska
- Division of Macroscopic and Clinical Anatomy, Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
| | - Benjamin Ondruschka
- Institute of Legal Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Gerald Pinter
- Institute of Materials Science and Testing of Polymers, Montanuniversität Leoben, Leoben, Austria
| | - Petr Henyš
- Institute of New Technologies and Applied Informatics, Faculty of Mechatronics, Informatics and Interdisciplinary Studies, Technical University of Liberec, Liberec, Czechia
| | - Niels Hammer
- Division of Macroscopic and Clinical Anatomy, Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
- Department of Orthopedic and Trauma Surgery, University of Leipzig, Leipzig, Germany
- Fraunhofer Institute for Forming Tools, Division of Biomechatronics, Dresden, Germany
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Tuset L, López-Cano M, Fortuny G, López JM, Herrero J, Puigjaner D. A virtual simulation approach to assess the effect of trocar-site placement and scar characteristics on the abdominal wall biomechanics. Sci Rep 2024; 14:3583. [PMID: 38351278 PMCID: PMC10864383 DOI: 10.1038/s41598-024-54119-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 02/08/2024] [Indexed: 02/16/2024] Open
Abstract
Analyses of registries and medical imaging suggest that laparoscopic surgery may be penalized with a high incidence of trocar-site hernias (TSH). In addition to trocar diameter, the location of the surgical wound (SW) may affect TSH incidence. The intra-abdominal pressure (IAP) exerted on the abdominal wall (AW) might also influence the appearance of TSH. In the present study, we used finite element (FE) simulations to predict the influence of trocar location and SW characteristics (stiffness) on the mechanical behavior of the AW subject to an IAP. Two models of laparoscopy patterns on the AW, with trocars in the 5-12 mm range, were generated. FE simulations for IAP values within the 4 kPa-20 kPa range were carried out using the Code Aster open-source software. Different stiffness levels of the SW tissue were considered. We found that midline-located surgical wounds barely deformed, even though they moved outwards along with the regular LA tissue. Laterally located SWs hardly changed their location but they experienced significant variations in their volume and shape. The amount of deformation of lateral SWs was found to strongly depend on their stiffness. Trocar incisions placed in a LA with non-diastatic dimensions do not compromise its mechanical integrity. The more lateral the trocars are placed, the greater is their deformation, regardless of their size. Thus, to prevent TSH it might be advisable to close lateral trocars with a suture, or even use a prosthetic reinforcement depending on the patient's risk factors (e.g., obesity).
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Affiliation(s)
- Lluís Tuset
- Departament d'Enginyeria Informàtica i Matemàtiques, Universitat Rovira i Virgili, Av. Països Catalans 26, Tarragona, Catalunya, Spain
| | - Manuel López-Cano
- Abdominal Wall Surgery Unit, Department of General Surgery, Hospital Universitari Vall d'Hebron, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Gerard Fortuny
- Departament d'Enginyeria Informàtica i Matemàtiques, Universitat Rovira i Virgili, Av. Països Catalans 26, Tarragona, Catalunya, Spain
| | - Josep M López
- Departament d'Enginyeria Informàtica i Matemàtiques, Universitat Rovira i Virgili, Av. Països Catalans 26, Tarragona, Catalunya, Spain
| | - Joan Herrero
- Departament d'Enginyeria Química, Universitat Rovira i Virgili, Av. Països Catalans 26, Tarragona, Catalunya, Spain
| | - Dolors Puigjaner
- Departament d'Enginyeria Informàtica i Matemàtiques, Universitat Rovira i Virgili, Av. Països Catalans 26, Tarragona, Catalunya, Spain.
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